Instructions
Start ̶0;Call of Duty: Modern Warfare 2̶1; on your Xbox 360 console and select ̶0;Multiplayer.̶1;
Click on ̶0;Xbox Live̶1; and then follow the prompts to sign in to your Xbox LIVE profiles.
Select ̶0;Find Match̶1; from the menu as soon as you are both signed in and then select a game type. The ̶0;Capture the Flag,̶1; ̶0;Domination,̶1; ̶0;Headquarters̶1; and ̶0;Sabotage̶1; game types give you the most points per match, so you and your friend will level up the fastest if you choose one of these for your game type.
Wait for you and your friend to be placed in a game lobby and then follow the onscreen directions to play the game type you selected. Since you are both signed in, the game screen will automatically be in split-screen mode. Stick together, kill any enemies you see and follow the in-game objectives to level up quickly.