Rush Tactic get a friend with a headset, and make sure you have one too. get C4 and the explosive upgrade to carry extra ammo. be assault and get anything other then an assault rifle to use the C4. have a partner get a UAV out then plant all your C4's on it, and with 2 or more people sticking C4's on it, at the range of (i think) 1-3 meters, it will destroy the bomb. you can also stick C4's on a jeep to do it solo. let the jeep fly into the enemy then blow it up. its good against tanks, buldings, helicopters (that fly stupidly low to the ground) and bomb sites.
Shotgun sniping (This is from youtube, its not my idea. i do not take any credit for it, im just spreading it get a shotgun, preferably one that is pump action (higher damage) get a slug and magnum ammo and you can basically snipe with a shotgun! i heard it has no bullet drop but i am not certain about this.
you should spesialice in engener assult the ump45 is asome u can hardly here it and the m16 kills realy fast recon is ok if you like sniper but the lame thing is the m24 is the best sniper the mg3 is not than grate g36 is better
the m24 isnt the best by far. i think its 2 more away, the SV89 err 98, it has 10 bullets per clip, it kills in one shot to the head, like all other bolt actions, it has the fastest bolt action reload and the fastest reload animation (rate of fire then) and it looks sexy in black plus its sights have the 3 ^'s and i like the look of them. the other scopes are easier, i do admit though. i use the m24 because i have the most kills with it, im on gold star 2 and im going for the... platnum? lol