First, go online and set your killstreaks to one or more of the following: Care Package, Sentry Gun, or an Emergency Airdrop. Then, go into a session and get the killstreak. Once done, get into a good hiding spot. Throw your red smoke grenade (killstreak) somewhere where you will be able to see it. Then, wait for an enemy to attempt to steal your killstreak but miserably fail. Alternately, if you have unlocked claymores, you can throw your red smoke grenade (killstreak) and set a claymore by it. It is a good way to get a lot of points.