The Outfit

Boost with a friend. Nobody plays online. Just let each other capture and get kills and don't end the match until you get more than 350 points. You'll most likely get this achievement while boosting the different kills achievements.

First, this doesn't have to be done in a Ranked Quick Match game. It can be done in a Custom Game and you can change the settings to give you more time, etc.

Second, in order to score points, YOU must be the one to kill enemies (calling airstrikes counts for you too). Enemies killed by your AI teammates including your emplacements will earn you FU (field units for buying stuff), but won't earn you any POINTS.

Whenever you are driving around in a vehicle, make sure YOU are the one in the gunner seat.

See my guide for the 18 points per minute achievement for racking up points quickly and efficiently.