I'm getting pwned on Black Ops, help!?

I always die be getting shot, camped on, grenaded, mauled, whatever I'm always at the bottom of the list, I never even get a kill sometimes! I need a good weapon layout, strategy, and some useful hints please! I'm level 30 right now and use a Stoner 63 with infrared sights and extended mag (I have warlord perk) I use a strela whatever and a frag, a concussion and perks are Scavenger, warlord, ninja. Help I need some way to survive! I play on Wii btw.