Team Fortress 2/Walkthrough

Engineer

 * Build a teleporter entrance near spawn point, go back to resupply before continuing. Move exit forward as team progresses.
 * Teleporters can be useful on both offense and defense.
 * Build a dispenser first, this will provide metal to fully upgrade a sentry.
 * Sentries have a limited range of sight, keep this in mind.
 * Sentries will scan in the direction aimed, if they have to turn around it is time wasted. Use the right mouse button to adjust.
 * In sudden death set up a dispenser, as medics and dispensers are the only sources of health.
 * Don't get in the way of your turret, it will kill you.
 * Stand back from your sentry, this will give you a chance to use your shotgun on any spys attacking it, before they can attack you.

Scout

 * Scouts capture points 2x as fast as other classes.
 * It takes 3-4 hits with the bat to kill a heavy.
 * In general, refrain from using the teleports.

Spy

 * Patience is the key to the spy, it's much easier to break into the enemy base if you wait till they are mostly respawning. Patience is almost required if you want to slip into their base. Take the long route into the base to lessen the chances of anyone seeing you, cloak liberally around corners in case an enemy is right on the other side. Once you are in they will likely take you for granted, and let you do whatever you want so long as you don't look overly suspicious.
 * As a spy, your main targets are sentry guns, medics, snipers, and heavies, in that order. Sniper and heavy are about the same, but depending on their skill and the situation you may want to take down one or the other. feel free to kill a demoman if he has a location well stickybombed. Other classes try not to take down, as they will just be more alert of you after they respawn.
 * You will slow down to the speed of the class you disguise as, but you can't go any higher than your default speed. For example, if you disguise as a heavy you will move at the same speed as a heavy, but if you disguise as a scout, you will move at the normal spy speed.
 * Choose carefully the class you disguise as, especially if they either don't have any of the class you choose, or only one of them. Disguise as a class that frequents the area you plan on attacking, such as heavy, demoman, or engy for defense, and soldier or demoman for offense. try not to scout, as if they are paying attention they will notice the speed difference. If in doubt, soldier is the safest disguise, as most teams have at least 2 of them, and they can do any job adequately, so they rarely look out of place.
 * Behave as if you are the class you are playing, it is not enough to choose the right disguise, you have to look the part as well. it helps if you have played all the classes a fair amount and have a good idea what they do in a game.
 * When you disguise, you give off smoke for a few seconds until you have your disguise on. This a very easy giveaway so don't disguise or change disguises in front of any enemies.
 * It helps to disguise as one of your own team, but a different class, so the other team doesn't know to expect a spy.
 * If an enemy starts shooting at you, do not change your behavior at all. Do not even look at them, they may decide you are not a spy, and let you go about your business. If you try to run away though, they will definitely chase you and very likely kill you.
 * AS soon as you are uncloaked/undisguised sentry guns will shoot you, so use your sapper before killing the engineer.
 * It takes a second to attack after un-cloaking
 * You cannot cloak/disguise when you have the enemy intelligence.
 * After you backstab, change your disguise. The guy you stabbed will be looking for you.
 * Hide in enemy base, wait for them to go on offense, disguise and run with them, Backstab as the are running forward.
 * Against engineer, if he is standing right behind his turret, and they often do, you can backstab and sap before the turret can turn around.
 * The engineer is your worst enemy, they are the most paranoid of all classes, and for good reason. given 15 seconds to yourself, you can take out all of his buildings if they are close enough together. When possible try to cloak past them, don't count on your disguise to fool him.
 * If you run right into an enemy going in the opposite direction, it sometimes works to immediately turn around and move with him to your base. He may think you were waiting for more allies to attack with. Slip away when you can, or kill him.
 * On 2fort, when assaulting the flag room, unless the enemy team is completely slack on spy defense, don't try to fool them. Most teams shoot anyone going into the flag room on sight. Try to cloak in behind them, and then sap/backstab.
 * Sometimes part of the spy is knowing when to switch to a new class. If the enemy team is so paranoid that they shoot anyone on their team who walks into the area, or just randomly shoots teammates, you have done your job, and are free to move over to another class. At this point it hurts them more to spycheck all the time than anything you could do as a spy.
 * It may seem obvious, but never cloak/decloak or disguise in front of the enemy. they will immediately shoot you.
 * Sometimes it works to call for medic and have the enemy heal you, but soon enough they will wonder why you aren't shooting, and try to bonesaw you. when this happens cloak, or try to stab anybody in front of you and run away. Mostly though, just don't call for medic unless you are about to die.
 * The revolver is actually a fairly powerful weapon if you are carrying the intelligence or capturing a point. If you can nail your shots most of the time you can buy yourself the time you need to get out of the line of fire. Don't use it when you can disguise and knife though, it is purely a back up weapon.

Medic

 * Uber charges faster when healing others to normal health, rather than at maximum health.
 * Pay attention to how far you can be away with the medigun and use it to your advantage. Gun continues to work even when facing the opposite direction.
 * You can transfer the ubercharge between people. This makes the charge deplete quicker, but can be used to uber multiple people at once. It is also a good way to extinguish many burning players.

Soldier &amp; demoman

 * During the countdown before the match begins, demomen and soldiers should wound themselves and allow medics to heal. Medics charge faster when healing wounded players. You can pretty much exit the gate with an ubercharge going if you start right away. (no longer 100% necessary, although still useful to help latecomer medics)
 * You can use rockets/sticky bombs to jump to places that normally cannot be reached.
 * Always keep reloaded.
 * As a soldier using the rocket launcher, aim for your opponent's feet. It is difficult to get a direct hit with a rocket (and if you miss the rocket will go sailing past your opponent doing no damage at all), but hitting the ground at his feet will ensure at least some splash damage. Unless they are backed against a wall then try and go for head shots. You'll probably miss but it will hit the wall just behind their head which will cause lots more damge then shooting at their feet.
 * A soldier takes less damage from rockets when rocketjumping. Remember this in frantic closequarters combat.
 * As a Demoman place your sticky bombs around the edges of doorways or corners, enemies won't see them until they are within range.
 * Also, by placing stickybombs outside of resupply rooms you can kill enemies as soon as they've spawned. This works especially well on 2fort.

Anti-turret techniques

 * Sentries take a second to spin up, so pop in/out of cover to destroy it.
 * For classes besides spy attack the engineer then the sentry, this is similar to "kill the medic first"

Anti-ubercharge techniques

 * Run
 * Use rockets/grenades to break the team apart this will stop the uber charge.
 * Counter with another uber.
 * Demo-men can plant fields of sticky mines underneath the uber pair. They probably won't even notice. Then get out of the way so as soon as the pair return to normal you can blow the mines.

Misc

 * Jump into water to put out flames from the pyro.
 * Kill the medic first! When you encounter a medic team up always aim for the medic first.
 * After you teleport you have a trail of sparks, which can make you more visible. Even if you are disguised as a spy these will show.
 * Protect teleports, it helps the whole team.
 * If you are a scout, generally don't use the teleports.

Sniper

 * Find spots where you have cover but can still see enemies.
 * Snipers can be good on defense
 * Remember People can see your laser dot. Keep it out of peoples sight so you can take them by surprise.

Tips for Utilising a Medic Ally
Even a single medic can help turn the tide of a round. Here are some tips to keep in mind when fighting along side the healers of Team Fortress 2:

Medics can not rocket jump: It's a no brainer really, but you would be amazed at the number of soldiers and/or demomen who will rocket jump into a window or onto a battlement and then call for a medic to follow them. The good players will hang over the edge to be healed then run into the ether. Or wait to be buffed so that the rocket jump doesn't take any of their permanent health.

Uber does not last forever: It lasts for 8 seconds. Enough to cause some mayhem or push forward a good offense or counter-attack. Please don't take it as an open invitation to run through to the back of the other team (in most cases) because by the time you get there it will almost have run out and we'll both be dead. A good medic will retreat (if necessary) before the Uber runs out, so don't complain if you're left alone in the middle of 3 soldiers, 4 pyros and a heavy.

A medi-gun can only heal one person at a time: Considering the lack of people willing to go medic you'll be lucky if your team has a single one available. That one medic will be Johnny on the spot in a hectic fire fight and will generally try to heal the person that has the least health or the people on the front line (fellow medics are also a high priority). If you have full health then don't slap the medic button 15 times and expect him to come running just because you want the protection, an inexperienced medic will latch onto you and your team will die. If the rest of the team is looking good and you're in a good position an experienced medic will know to latch onto you. I know the E button is easy to accidentally press, so I'm starting to learn to judge if it was an accident or not. 5 - 10 presses is not accidental.

Medics are a primary target: Almost every strategy guide I've read has put medics at the top of the "To-Do" list. Regardless of the class you are, try to protect your medic. Your team will tend to live longer if you can take out that scout or pyro making a B-Line for him. An experienced medic should be able to dodge most rockets and grenades but will retreat up to maximum medi-gun distance (or more) if someone gets too close, especially if he has over 50% charge on the Uber. That's a bitch to lose.

Medi-guns need line of sight: They do lock on to a target but they don't work through doors or walls and the ability to heal around corners is extremely limited. This is mostly important in the tight corridor sections of the maps. If you charge around a corner too far or dodge to the side through a doorway then you will force the medic to follow you and open himself up to attack (see previous point). Instead, try to stand right on the corner or in the doorway so that you can enjoy the smooth sensation of sustained healing whilst laying waste with your weapon of choice. It will also put you in a much better position to retreat for healing if you get too damaged.

Glance at your HUD: When a medic has latched onto you a display will show up in the bottom(ish) centre of your screen. It will tell you who the medic is and the charge % until he gets Uber. Use this to your advantage and don't waste your life when your medic is 10 seconds away from making you invincible. Voice communication is a huge bonus in this situation, even if it's just the medic telling you to hold off for a few seconds. If you're good at your chosen class then telling the medic ahead of time when you want the Uber is also immensely useful. e.g.: "(Uber) At the top (of the stairs)" - while charging up some stairs. An experienced medic should know what you mean if you just say "At the top", assuming he is at 100% charge. You might want to add the words in brackets if you're unsure.

Healing takes time (aka. don't be a hero): This carries on from the previous point: having your own personal medic does not mean you will live forever, so check your health when you can. Heavies especially tend to take a pounding whenever the opportunity presents itself, so your 300 health can be brought to 0 in a matter of seconds if you're not careful. Even a medic can not save you from 4 direct rocket hits plus sustained minigun fire. Communication is also extremely important here because your medic will have an icon with your current hit points. If your medic tells you to pull back it's because you're just about dead. Most medics will keep themselves behind cover as much as possible, so if you need to retreat it should be a simple matter of following the medi-gun trail towards the medic (and said cover).

Know where your medic is: I know this is asking a lot considering the enemy will be your primary concern. But if you run out from cover chances are the enemy will see the medi-gun trail and be ready for the medic following you (snipers especially). If you come under heavy fire or a pyro jumps between you then your medic may not be following you to your destination and it might pay to either wait behind cover for him to catch up or try to take out more immediate threats. It would also pay to run your cursor over him to check his status when you get a chance. A medic that is almost dead is unlikely to want to charge head long into the fray. Knowing where your medic is will also increase your longevity in the field if you retreat towards him instead of away from him. The closest cover will not be the best if there's no healing there.

Do you really need that health pickup: A medic in Team Fortress can not heal himself. His health does replenish automatically but it is painfully slow and a severely wounded medic can take up to a minute to heal back to full health. That's one minute spent not helping your team push forward. Before heading straight for the nearest health kit make a quick scan of the area to see if there are any medics that might need it. If you are already being healed then leave it for someone else and find some cover to hide behind. You will also be assisting the medic in getting his Uber more quickly if you let him heal you.