Successfully complete one of the following tasks to get a trophy:

First Mission (Bronze): Play an Objectives mission online for the first time.
Probie Commando (Bronze): Reach commando level 5.
Mission Handler (Bronze): Host games with a combined session playtime of 1 hour.
Demolition Expert (Bronze): Destroy 20 control panels.
Hacker (Bronze): Upload 20 blocks of data.
Weapons 101 (Bronze): Get 20 kills with each of the six primary weapons.
Globe Trotter (Bronze): Play a complete game on every map online.
Elite Commando (Silver): Reach commando level 15.
Boot Camp Beast (Silver): Complete all Grunt and Jarhead Boot Camp missions with a Commando Medal score.
Crash And Conquer (Silver): Win 20 online games.
Survival Of The Fittest (Silver): Have all three survival bonuses activated at the same time in an online game 10 times.
Crash Commando (Gold): Reach commando level 25.