Hmm... Pretty much what you should do is get an AK, an Awm, and the QBZ with any pistol's you prefer. Remember to get all 3 types of grenades and have speedy c4 defuse and the expand slot for the grenades. Also, why not spin some Deagle Camo Crates? Who know's you might win.
EDIT: If you do HM/MM/ZM you should get the rpk then, unless you wanna troll around in pubs.