How do i rank up in Gears of war 2?

Alright here's the totally ridiculous story. I got to a rank 2 in gears the day after the game came out. I'm pretty good at the game, my Kill/Death is about 1 in almost every mode and i am higher on the leaderboards than most 3rd ranks. I also play, alot. Mostly elimination but sometimes territories and sometimes wingman. Any advice?