By now everyone knows about Left 4 Dead, but still not many people are playing it. When you do decide to step into the world of zombie eradication here are some tips to help you survive the zombie apocalypse, and make it to see your next sun rise. These tips can help you out with the single player campaign and the online campaign.

1 - Play with the volume cut up loud enough to hear. Everything has an audio cue that signals when a horde is approaching or when one of the special zombies is in the area. By hearing them you will stand a better chance of being able to handle it with little to no damage as apposed to being running head long into danger.

2 - When you hear crying CALM THE HELL DOWN. I don't know how many times I've seen people who are all over the place shooting zombies only to run right into a Witch. They are fast and very dangerous because they are much stronger than Tanks. it's a trade off for the fact that they don't bother you as long as you don't bother them. When you here crying take these steps to avoid getting your face ripped off.
A-Cut off your flashlight. it has the same effect on her as sunlight has on a gamer after being up for 22 hours.
B-Move slowly. Running around is the fastest way to accidentally run into her.
C-If you see one and see is near where you need to go, crouch down and move past her slowly.
D-Listen to her as you move around her. If her crying stops and turns into a low growl MOVE THE FUCK BACK
E-If you need to fight her aim for the head. Also setting her on fire really doesn't help. It just makes her mad.
F-Lastly DON'T STARE AT HER. Just like a prom queen with a small zit. If you stare, YOU DIE!

3 - When you hear the sound of a Tank get ready. When you finally see it pump everything you have into it while you back away. If you are far away from the walking bicep with eyes he will pieces of the ground at you. They do more damage than getting punched but they are easier to dodge. Also When the Tank gets close to you, run away don't try to jump away. If you get hit while jumping you will be pushed back much further than you normally would. If a Tank every incapacitates a team mate just melee it from behind to get it's attention then RUN LIKE HELL!

4 - The pipe bomb is your friend. It not only causes a nice little boom, but it has the added benefit of drawing all of the infected in the general area to it. So while they try to punch and kick it, you can get to safety while they get a nice surprise.

5 - Molotoves and gas cans are really best saved for defense. When you are waiting for the rescue vehicle it is for the best if you set up gas cans in area where the infected might enter. Set them off to create a wall of fire that will slow them down. Molotoves work the exact same way only they are thrown.

6 - Stay close to each other. The closer you are the less likely someone will be injured by the Smoker or Hunter. And remember if you see a Hunter in mid flight coming towards you, melee him instead of shooting. You are better off knocking him away instead of trying to halt his attack with bullets.

7 - When you get face to face with a Boomer, use your melee attack to push him back. When playing with others make sure the Boomer is nowhere near your team before you blast his fat ass. If you do get Boomer bile on you either back yourself into a corner and start swinging, or try to run the way you came. The first option works better because one your melee attack knocks the infected into one another, so you can keep them at bay while your vision clears up, and you don't run the risk of getting lost because you ran the wrong way.

8 - Get yourself a boomstick. The shotgun is much better than the machine gun and assault rifle. They later 2 run through ammo very fast and aren't as powerful. It is better to use the pistol/ duel pistols for targets further away and switch over to the shotgun when the infected get too close for comfort. But be careful, the shotgun can take out multiple infect with one shot, but they are slower to reload, and you have a higher chance of friendly fire due to the spread.

9 - Even though I consider the shotgun to be the better weapon, the entire team shouldn't use them. When playing with 3 other people the weapon layout should be as followed. 1 shotgun, 2 assault rifles, and 1 hunting rifle. The following formations will help when inside, and when out in the open, on the Expert difficulty.
Inside - The shotgun should be in the front, and should be the one to open doors. One assault rifle should be behind the shotgun, to help and lay down cover fire while he reloads. The hunting rifle should be in the middle or in the back. They need distance to be effective so with 2-3 guns between them and the infected they should be able to take out enemies that a far away and help thing any hordes that might pop up. The last assault rifle should in the back or in the middle. In the back they can bring up the rear, and catch any special infected that happen to be following your group, but in the middle they can offer up addition cover fire for the shotgun.
Outside/ Open Spaces - You should all be in like a diamond formation. The shotgun should be in the front, plowing through the infected. The 2 assault rifles should be watching the sides taking care of any nfected just hanging around. Also they should help with thinning the horde. Last the hunting rifle should be in the back acting like a scout. listen for the sounds of the special infected and try to locate them. You could actually take them out before they become a problem.

10 - If you are going to use the mini-gun make sure you are covered. It is better used online because you can make sure each one of your teammates has one of your three blind spots covered. When playing single player make sure you get off of it when you see that one of your teammates is in trouble. Nothing is worse than letting go to turn around and see 50 or so zombies smiling at you will one off in the corner holds up a sign saying "You know you fucked up, right?"

11 - Lastly always close doors as you progress. When playing by yourself the computer controlled AI will close doors if they went through them last. But every now and then it's up to you to try and close doors. A closed door can by you some time and it can give you an opportunity to take down some infected without them getting to close, and they bash it down.

If you keep these tips in mind then you will have no problem clearing all 4 campaigns in the game. And then once you do that why not give expert a shot? When you do decide to tackle expert, all i can say is stick to high ground and do what Bill suggested in the intro. RUN...and SHOOT.