When you play Black Ops you want to make sure your classes are set up right.

When you play hardcore games, your classes should be set up for more stealthy setup like:Ghost Pro its a really helpful perk since everyone uses a spy plane kill streak. And you want to make sure your guns are silenced, that's useful also.

Games like domination, headquarters, etc. I find that Hardline Pro is a very useful perk when using a care package, you could turn ammo into a Attack Helicopter.

When you play Free For All, Hardcore or not, its useful to use Ghost Pro. Also, a silencer is a good attachment. Stealth is a good advantage in Free For All game types.

The guns I mainly use are, the Commando and the Famas.

In objective games its good to use higher kill streaks, since you get a higher kill count. When you play in games like Team Deathmatch and Free For All, you want to use a lower kill streak since you dont get alot of linked kills.

I hope some of this info is helpful since this is kind of a gay tutorial(: But any way if this helped, rep it.