Get more kills, capture more objectives, die fewer times, and play modes other than deathmatch. Those are what determine how fast you level. All the rest is just unique to the player and dont make enough difference to worry about. Its just what you like and have the points to afford.
I use Slight of Hand (Slot 2 Perk) because of the faster reload times, and when you get it up to pro you raise your gun up to aim down sights faster. I also use Hacker (Slot 3 Perk) so I don't get killed by claymores as often and I would use either Hardline (Slot 1 Perk) or Ghost (Slot 1 Perk). As per weapons or kill streaks that is really up to the player.