Cold Blooded and Ninja Pro pwnz. Are you guys using upgraded headsets? I initially bought some Turtle Beach X1's then upgraded to the X41's....they are amazing. I can hear people approaching, reloading, and all.
I mainly stick to Hardcore Team Deathmatch with a bunch of my friends. Even though you can get more points with other games, I don't find them as fun.
I also didnt care about K/D much when I first started. I was doing a lot of FreeForAll just to get my weapons achievements quickly so I've been slowly building my KD back up. I believe I'm a 1.07 or 1.08 now and steadily rising.