Pick a Suitable Class

• While there is no class that is necessarily better or worse than another, each one has very situational usages, so a diverse mix is often crucial to team success. For example, do not choose to be a sniper if there are already three or four of them on your team. Pick a different class that can complement other players. If there are no engineers, opt to be one and setup useful teleporters and dispensers for your team. If there are no medics healing the wounded, it is a good idea to take that role.
  
  

Learn the Classes

• Each class excels over all the others in one or two specific areas. For example, the scout can run fast and can capture strategic points necessary to win capture point maps twice as fast as any other class. The heavy has a lot of health, and when he is being healed by a medic, the only thing that can kill him with one shot is a fully charged head shot from the sniper. The demoman and soldier can leap huge distances by detonating their explosive weapons underneath them as they jump. Learn the strengths and weaknesses of every class.
  
  

Play as a Team

• Attack, retreat and defend areas as a group, and use support classes to help the offensive players. For example, medics are very important to keep the health of those fighting at the front in a good state. More advanced and quicker strategies can be planned and communicated if you use the voice communications in the game. Stay in contact with your team and know where they are going at all times to be in the best position to win games. If you do not have a microphone, press "T" to bring up the in-game text communication tool.
  
  

Check For Spies

• "Spy checking" is the practice of evaluating your teammates to make sure they are not disguised enemy spies. Normally, when you walk into a teammate you more or less glide through with very little resistance. A spy disguised as an ally, however, will glow his team's color briefly and be more resistant when you bump into him. He will also visibly take damage when shot (as opposed to teammates, who will not) and can be set on fire by the pyro class. It is important to identify disguised spies because they can kill you and your teammates instantly from behind, and they also sabotage the engineer's buildings.