[El Fangel]

If you see something move, shoot. If you hit there will be white x where your crosshairs used to be, nervous about a room, frag/flash/stun if you see a white x, it damaged/hit an enemy, if you see two white x's, there is more then one.

What Kalyx said about being paranoid.

For you guys, I would try this set up here

Any gun you have with silencer
Any shotgun you have with silencer
Sleight of hand (helps reload and later aim faster)
ColdBlooder and if not, Hardline
Commando (increase knife distance and later no fall damage)

Use
UAV (shows enemies positions, if you want to hunt or avoid is up to you)
Care package (you will get a can of red smoke, make sure there is nothing above you and toss it on the ground, then move away a little as there will be a crate dropping and it can kill you, crate will have ammo or a random killstreak (anything from UAV to AC130)
Sentry Gun (works same as care package, except the sentry gun can be place somewhere you are not, great in a high traffic area as it cuts off movement that way and also great because alot of the time, the AI in the gun is smarter then and watches your back better then your teammates) great for noobs who get a 5 kill streak, as they can run and hide for a bit while racking up kills)

Ill try to get you two into a private match with me to help you out more.

Add me on XboXlive Mackem.

Perhaps I can help you get used to the maps by showing you around.