Even if you shoot well in Team Fortress 2, make yourself better by learning how to use your ears for this game. You can be more careful and dangerous by just listening to the voices and noises around you. It will definitely prevent you from dying more often and recklessly. Get familiar with each of the classes' dialogues as well as the unique sounds coming from each of their weapons. If you're a spy and happen to hear flamethrowers nearby, it's best to be extra careful going further up ahead since pyros do the best job of exposing you.
You should take think twice on rounding the corner if you happen to hear the noises of machine guns or loud explosions; that probably means Engineers, Soldiers, or Demomen, three classes that deal heavy damage in the game, waiting for a poor fellow to carelessly wander into their midst. Get used to the sound of the Heavy's powerful minigun; if you hear that anywhere, think twice about going down the stairs, going underwater, or turning the corner. A Heavy often travels with a Medic, which makes a formidable pair, and you alone will be no match against them.
How well you listen in the game works both to improve your defense, so you won't just wander into enemy fire, and to strategize your offense, so you don't have to always attack your enemies directly. Don't always be in a rush to capture that flag once you're in the enemies' intelligence room; listen and see if you hear any suspicious sounds like sentries up ahead. A disciplined listener in the game will have an easier time to dealing with many situations; it will give you a split second to prepare against your opponents.
Taking notice of what you hear is not just about being cautious. If you're in enemy territory and happen to hear someone say “Building a sentry” or the sounds of a wrench pounding on something, that means Engineers are around. You can do your teammates a favor and see if you can launch a surprise attack on him before he completely builds his powerful sentry gun. If you hear an enemy yelling "Medic!", go and finish him off because he is probably low on health.