I don't like the word "camping" because were just being tactical, were not cheating in any why, just like when people call the grenade luncher a "noob tube" i can hit inside of any visible window on any part of any map weather im 5 feet or 500 feet away, almost guaranteed in 1 shot and im not a noob. Heres a tip for every level for people who do not like to run around in a match to much, If you want to know suggested classes i already have a post on that its under multilayer for beginners, multilayer for intermediate, multilayer for advanced. Good luck.
Afgan:
If you pause and look at the map on the left side is where the big hill is located, lay a claymore on both ways to get in to that area, snipe a little after a few shots go to the tall grass with an assault rifle with heartbeat sensor and play the waiting game. If no one comes repeat the process, this is good for probably 10 kills max if you can pull it off.
Next good spot is on the top of the map there will be 2 grassy areas and a bunker, the grassy area closest to the bunker has a little boxed off barrier, the one with 8 crates, a barrel, and a small sandbag area. On both sided lay a claymore slightly aiming that direction. you can now safely snipe and if your compromised you have lost of grass and a heartbeat sensor on an assault rifle.
Derail:
Theres a building on the top left of the map, on the 3rd floor you can bust a window and go out on a ledge, you have no cover from there but sniping there you can get kills, usually between 5-10 unless your a good sniper. Use lower kill streaks, lay a claymore by the stairs and ladder and you will be safe.
Theres a building in the center of the map, lay 2 claymores one on each side, use snipers grenade launchers and whet ever else you like, depending on what kind of people your playing with you could get 30 kills with high kill streaks or barely brake a 1 kill death ratio depending on how many of the other team trys to get to you. Use your best judgment.
Estate:
If your ever in a match and you see me, i thought you this spot so i have dibs on it, this is one of the best levels in the game, On estate theres a big building on the bottom of the map, enter, on the 2nd floor theres a bathroom, then a big room with a bed and a bathroom in that big room, theres only 2 ways upstairs, lay a claymore both ways, recommended to have danger close on if someone is inside, and wait, you will easially get chopper gunners and ac-130's here, this map i went 91 kills 10 deaths, and it was my best match, other then that match ive only ever been able to get in the 40's This spot is so good ive never bothered testing any other areas.
Favela:
Theres a building on the top left of the map with a blown out side, and only a 2nd floor that you get to by stairs. Stay in that building lay your claymores on the 2 ways up, i suggest having good assault rifle aim because sniping here is not the best idea but you can get long range kills.
The large building on the right of the map, get on the roof lay your claymores and its a good area, theres little cover but you can get a few lower kill streaks here and most of the people end up walking by you. Just know your not covered well.
Highrise:
Not a great level unless your in a free for all, but in free for all heres a good technique, on the bottom left on the map in the building theres a room, on the map theres a semi circle where the desk is, in the room on the other side of that wall is a bunch of cubical's. Theres a sofa with a plant next to it, place a claymore next to the sofa facing the wall on the bottom of the map, on the other side of the room theres a copy machine facing a room with glass walls, if your facing that wall you'll be facing left on the map, now while facing that wall move right a few steps and back a few steps you'll notice you can back up a little where theres a cubical wall to your left a plant in front of you and a trash can to your right, lay the claymore facing the glass room and your good to go, just hide in the room that has the semi circle desk.
On the left of the map theres a building that you can climb, get on the building and face the left of the map. You will see a crain, jump on it and jump on the one behind it, follow it up to the building and you can enter the 2nd floor of the building on the top of the map, good for sniping.
Invasion:
On the bottom of the map theres a building that you can get on by 2 ladders, lay your claymores and kill.
Next to the building on the right of the map at the bottom theres a building thats trashed on the 2nd floor, another good spot.
Next to that one theres another building with a van in front of it, thats another good building. Having 3 people one in each spot on headquarters and 3 people capturing the headquarters would be great.
Karachi:
Another not so good level, on the top of the map theres a building, on the 2nd floor theres a small room with a small bed and a dresser, lay your claymores protecting you in the building and play, tough to get kills here
On the left or the map theres a few rooftops you can get on, moving from one to the other as needed, lay your claymores and go for it, you wont get many kills
In the middle of the map theres a rooftop that is very high and has a great vantage point. Good luck this is a tough level
Quarry:
On the right of the map theres a building with 3 entrances and a tank lay claymores on the big door and the small door across from it not next to it, snipe from the window on the open doors side, when your compromised simply kill who ever comes in. This is the only spot ive managed to find so far.
Rundown:
On the bottom a little to the left of the map theres a building with stairs in the back, go up lay your claymore and its a good building.
Jump out of that 1st buildings window and jump to the other rooftops further away on your right and theres a good vantage point of the other teams spawn.
In the middle slightly on the right of the map theres a building, on the map you will see 3 bridges, the 2 on the bottom both lead to this building if they would be extended, good view of most of the map.
Rust:
Get on the top of the center area, best vantage point and you cant bee seen unless looked for.
Scrapyard:
On the top of the may is a building, lay your claymores tactically and go for kills.
On the bottom of the map is another building, lay your claymores on the big door and the one furthest away from it and you can kill from the 1st 2nd or 3rd floor, easy as 1 2 3
Skidrow:
On the bottom left is a building, lay your claymores and from that building you have a perfect view of the tunnel people like to come down.
On the bottom center is a building great for sniping from and using the turret. Lay your claymores tactically and your done.
Sub Base:
On the left of the map is 2 buildings attached by a small bridge, lay your claymores and stay behind cover as much as you can this is a great spot and a great level, you will probably be found out and killed a lot at about 1/2 way through the match to play smart.
Terminal:
Sometimes a great level sometimes a pain, to the right is a little area, lay your claymores and you have a great view of the map in that area
On the right is a plane you can get into, i found most people will not go up the side entrance so lay your claymores at the other 2 and kill from where ever in there you find best.
Underpass:
I'm not a big fan of this map but ive grown to like it better then highrise, on the left of the map is a building, theres 3 ways in, downstairs door, upstairs door, and a window nets to the upstairs door, most people wont use the window, lay your claymores at the door, and kill
Wasteland:
No true best one spot the best i can suggest is find a building on the outside of the map and lay your claymores use the windows to snipe, or lay prone anywhere in the grass preferably by an entrance/exit to the underground area in the center.