You have got to be on wi-fi for this.
Go to team match, and if your team is losing, at the end, switch to the winning team and you won't lose any wi-fi points!
Pick the oo agent in parking lot and climb the ladder to get onto the roof of the buildings. Before you do this, find a sniper rifle and pick it up. Right after climbing the ladder lay a mine at the entance of the ladder so that nobody else can come up. just stay up on the roof and continue to snipe people. This is an efficient way to camp and get lots of kills.