Read the following -

[marq=down]
Main weapon - MG36 (the second MG unlocked)
Secondary - Stinger
Perk 1 - Blind Eye (preferably pro - you get more XP if pro)
Perk 2 - Hardline
Perk 3 - Whatever

Killstreaks - Sentry gun, Attack helicopter, Strafe run

1st round - As usual, one person from each team goes to spawn, gets the 3 kills, plants/defuses bomb for sentry gun. Fine

2nd round - Same again, one person goes to the other spawn, gets the kills then both players getting the kills meet up at the most open bomb site - the bomb site which has no tall building near it. Now, one person calls in their Sentry gun airdrop but make sure that the player on the other team is standing quite a bit back so they can look all the way up and shoot the airdrop helicopter with their MG as it drops off the Sentry gun. This will get you 6K XP just for shooting a helicopter you usually wouldn't. Now, knife the sentry as usual and the other player who hasn't called in their sentry yet calls in their sentry and the player on the other team, shoots that down and gets the 6K XP as well as the XP for knifing the sentry. Next, if you have enough time, one person calls in the attack helicopter. The player on the other team shoots the attack helicopter with their MG. If you have blind eye pro, this will take around 20 bullets. Time will run down while the attack helicopter comes in and gets shot down so get the player who has the bomb call in the helicopter first so that when the player without the bomb is shooting the helicopter, they can plant it so you get 45 extra seconds for the bomb timer. Now, the player who needs to defuse calls in his attack helicopter and the other player does the same, shoots it with their MG. Then defuse bomb, round down. Easy.

3rd round - This round is pretty much the same. You will have another sentry gun so you know what to do with that once you have killed the non-playing characters at spawn. So do that, then one player calls in strafe run and you shoot the middle helicopter with your stinger you then do the same with either the right or left helicopter. Then, once you're out of stingers use your MG to shoot down the last remaining helicopter. Then, do the same with the other player.

That's how you call in and take out all the killstreaks pretty much. I only wrote this tutorial up to round 3 as that is when all the killstreaks are gained. For the rounds after round 3, it's just a repeat of the previous rounds.

The key to gaining more XP isn't in the order of calling in your killstreaks as so, it's just the way in which you destroy them.

If one of the players (or both) who are getting the kills does not have a stinger, get the players who aren't getting kills to pull out their stinger so that you can pick it up.

If you have any questions, feel free to ask them! Hope this helps!

This method gets you about 100K XP more each game with double XP.

Credits to FetusFlipper

ADD - imFunqh