So have been looking a lot at this sub-reddit since launch and have learned quite a few things and was thinking we could try and compile it into one large thread.
Some tips/tricks I've seen so far:
Specialist package has got to be the best for leveling. Using hardline it takes 1,3,5,7 kill(s) to get the 200 points for getting the perk. Also an extra 50 points for each kill after 7 is amazing considering your extremely effective with all the perks.
Another thing I love about the specialist package is that you get more kills with your gun rather than spending time using a kill streak such as osprey or AC130. I am currently working toward gold G36C and I want that bad boy soon.
I believe this will be fixed but as of now i only use EMP grenade because killing a SAM or a Sentry seems to add a kill to my point streak? I can kill the equipment without putting myself in danger and I get a free kill toward my point streak. At least untill they fix this of course.
As effectsfire pointed out this is not a bug! Evidently this is intentional to encourage people to destroy point streak rewards. So take out those stingers and replace their point streaks with yours!
EDIT: I believe this applies to capturing/destroying objectives as well.
Kill confirmed seems to be the best game mode for leveling. Me and my buddy just share half of our kill points by letting the other take the tag. We are always getting a great amount of points. I only use specialist so I don't run into the problem of having to try and get a tag after I killed a guy halfway across the map with a predator. Denying kills is also great. One time I ran through and collected 6 tags at once. Quick 300 points not counting the kills themselves.
As anEnglishman pointed out, untill now SND, I believe, has been considered that quickest way to gain xp. The only problem is that it is highly dependent on your skill because dying early in the round may mean no points at all.
That's about all I can remember at this point. Any tips would be great and I will be editing this if I get any.
Tips from comments:
ReeColi: When people call out strafe runs, shoot the helicopter in the middle. It blows up the two adjacent helicopters as well, and adds 3 points towards your point streak.
rh1nos: Try putting only 1 point streak on (e.g. UAV) so you can keep cycling through the same point streak. This will help you complete that point streaks challenges a lot quicker.
twenty0ne: Use marksman, even if you don't snipe. Seriously. It's a huge advantage to more easily see where enemies are at when they're partially obscured by cover or blending in with the environment.
loganz: Ive been running support killstreaks (UAV and Ballistic Vests ONLY). If you play groundwar, you throw down your ballistic vests at spawn, and everyone picks it up lol.. its 50 points a pop.. 11 team mates, and it stays there for a while... ive been consistently getting 8000-10,000 points per game (without double xp). Also, save your double XP for later in the prestige, when you are close to hitting a bunch of challenges (10,000 XP etc).. There is no sense in using Double XP from the beginning, since points come slow, and you have no challenges to complete.
BigStein: If you're using the FMG9 machine pistol, you know how there is the initial flip animation? Well that only happens the first time you switch to it, so switch to it (and switch back to primary) immediately when you spawn so that the animation doesn't happen at a bad time.
EDIT: At this point I will just be placing tips up here. If you like the tip please find and upvote the guy who wrote it