Left 4 Dead/Tips

General

 * Stay with your team. Pulling a Leeroy Jenkins in Left 4 Dead (especially Versus mode) will get you killed quickly, you will need to rely on your team to back you up when you get in deep trouble.
 * Nominate a leader. Before starting a campaign, it would be best to select a leader to follow, because having multiple people saying, "We need to do this", gets very confusing and annoying. Suggestions may be offered to the leader to help the party along.
 * Train with every weapon, this will allow you to fill any roll needed at any time so you will be a very balanced teammate.
 * Take time to prepare for Crescendo events and Finales. Without a plan, things usually go worse than what they need to.
 * When using the SMG or Assault Rifle, fire in controlled bursts. Exceptions include firing at the tank, witch, or a narrow corridor with a horde on its way.
 * Conserve ammunition. It is always wiser to use your pistols and save your primary weapon for emergencies. The last thing you need is to run out of ammo with a witch or tank bearing down on you.

Advanced

 * Train yourself to be self-sufficient by doing single player campaigns solo. Open up the console by pressing the ~ key and typing "kick (survivor name") without the quotes or parenthesis and go through the campaigns with only 2 bots, then, when you feel up to it, only 1 bot, then finally, by yourself.