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.