Board Thread:Questions and Answers/@comment-108.36.147.216-20121122030509/@comment-1486311-20121122034701

A single Certification Point, or Cert, is accrued when you earn 500 experience points. Working together in squads or platoons will yield you bonus experience points for several actions like rearming, repairing, healing, or capturing an objective set by your squad leader.

In other words, the better you do, the quicker you'll pick up certs.