The class you choose in call of duty 4 is the type of guns/grenades you will be using.
It all depends on what you want to do. If you want to snipe you would obviously pick a sniper class.
When you are high enough level to create a class, that is when you should read this (which shouldn't be long considering its level 4 I think). Ok so if you are going to be sniping pick the first sniper you have, by far I think it's the best. Put stopping power on and if you can put claymores as your perks, if you cant use claymores yet then use your special grenades, the last perk is up to you unless you have iron lungs. Don't put steady aim because that only increases accuracy when you are shooting from the hip not when you are zoomed in. Now here's a mistake people always make, they think they've found a good spot so they will stay there and maybe get one or two guys, guess what your screwed, the kill cam gives you away so always move around.
If you like assault I love the m16 I have red tiger on it with my ACOG scope and its beastly. Again I say you put stopping power as your perk and this time if you can use extra regular frag grenades, and for your last perk I would say use martyrdom because if you charge in and die a lot like most people do then the people you DIDN'T kill will probably die, if you like to stay back and kind of pick them off then I say use last stand because if someone shoots you from a distance whats a grenade gonna do right?
LMG's are ok but I personally don't like them. You don't need stopping power with them but if you are going to use them put on your sleight of hand perk because when you reload, your screwed. Other perks I don't care what you use whatever floats your boat.
SMG's are awesome. put stopping power on as a perk…. Again, unless you have a p90 then use the double tap perk trust me its better than you think with the p90. Use martyrdom with it because SMG's are close range. Also if you are using double tap with the p90 use bandolier as a perk because you will run out of ammo trust me.
Shotguns are shotguns. You don't need stopping power cause it's a shotgun also put sleight of hand on as a perk and martyrdom. Maybe just for fun put eavesdrop perk on so you can hear where they are going then jump out on them.
If you have over kill do what I said with all the weapons but try to combine them together, that worked out good for me.
Team death match is a death match. I don't recommend putting silencers on your guns for this because your gonna die no matter what. Just do what I told with all the other classes same this I just said for headquarters and every other game…Except search and destroy!
If you are playing search and destroy I say put silencers on every gun you can. Use all the perks I said earlier but if you are sniping put over kill on with your choice of backup weapon (just not another sniper!).
Headquarters gives you a lot of experience because you get 5 points every 5 seconds if you have the HQ.
Im not saying any of my secret sniping spots but lets just say there not supposed to be there (not glitches but if you go in the right way your in a nice spot) BEWARE! If you find a spot keep it to yourself and you should still be able to die, if you don't then it's a glitch and you should leave it before you get reported for glitching!
I hoped this helped you well good luck and such and such. See you on XBL (gamer tag is Phlippin Sweet that's pronounced flippin not philipine )