ok here is my suggestion which i gave to another guy who had the same questions only a few inches away from ur thread....if only you'd use the search tool. well anyways...
SCAR SILENCED
JAVELIN
SEMTEX/2 STUN GRENADES (take less time to throw than flash and people can still spam randomly when flashed but when stunned cant aim at u quick enough)
SCAVENGER PRO
COLD-BLOODED PRO
NINJA PRO
PAINKILLER
KILLSTREAKS--7 KILL (HARRIER), 11 KILL (CHOPPER GUNNER), 25 KILL (NUKE)
stay on the outsides of the map and go around killing people...if u find a good spot only get 3 kills there and then move...they WILL come and kill u if u stay. Once you get harrier...as bad as this sound, but u kinda need to camp and if ur bad at camping, just camp and dont worry about getting kills....wait till your harrier is gone before u call in your chopper gunner or u will be fighting urself for kills...remember there is a time limit and ammo limit so dont spam randomly with ur Chopper-G hoping to kill people. once the chopper gunner is gone, u must be very very cautious continuing ur circulation around the map very slowly and picking people off as you go in order to reach the 25 kill mark. for some maps this circulation technique does not work and you have to be in one place that not EVERYONE goes to and then look at the hotspots to get the 7 kill. I have gotten many harriers that dont result in nukes. The best game mode to do this in, for me, is domination. dont worry about flags unless u or the other team is getting slaughtered since the longer the game, the more time u have to get a nuke. Note: this technique will not immediately work, it takes practice to get it and while it is not working, do not get discouraged, continue using it and you will be rewarded. ) I hope this helps, for i have gotten 21 nukes using this method and another 10 using my sniper class (with intervention, although not many people like the intervention)....if u have any questions, message me on NGU or PSN: ATREYU9A7X