Delta Force: Black Hawk Down

Take an assault soldier with a M16 M203 or carbine 15 M203. Shoot them at the top of the broken buildings. You may might kill snipers easily if they are up there.

Combat Medical Badge: As a medic, save the lives of three teammates
Delta Cross: Get ten knife kills
Distinguished Service Cross: Get five hours of playing online
Headhunters Medal: Get five headshots
Hill Giant Medal: Get 10 minutes on Hill
Infantry Badge: Get 50 kills
Meritorious Service Medal: Win 10 out of 20 games
Purple Heart: Get saved five times by a Medic

Have a Satchel Charge or Clamore and Grenade Launcher or any other gun mode. When your are near your flag, put down one or two satchels or claymores around it. Then, camp out somewhere that is elevated. When some one steals your flag, either detonate the satchel or blow up the satchel or claymore using your grenade launcher or gun.

In Large Terrain, when going to save someone that is in the middle of nowhere with snipers everywhere, pull out your "syringe". Crouch, then run towards him. When you are near the person, run over him holding Fire. Keep circling him and you should have saved that person.

For Overload, get a spawn point and wait for some snipers to spawn. When they die, get on the ground and crawl to the soldier. By doing this you probably will not get killed. For Shadow Of Death, try to go to a spawn point with high hills. By doing this you cannot be seen. When a sniper dies, use the method described earlier and you should have some easy saves.

Once the mission starts, run in front of the last AAV. Jump on the front of it to get an easy ride to the end of the mission. By doing this, you will be on top of it when they speed up and will not have to catch up. This results in you completing the mission faster and easier.