The best part about insurgents on buhriz, is the fact that you can set up your mg on a stairway, and lean left and right to get cover and make picks. If I ever run with the MG I usually do this and well it's pretty effective..
On samahaw (don't know the map name bro) and the night version I usually rush to d and sit inside the door way crouched looking outside. That way I usually get a clear view of who's coming to get me, and if they flank inside the door way it's an easy shot as well. If I've got a buddy with me I usually go upstairs and cover c and B captures pretty well by myself, although if there's a lot of pressure a 3 man setup would work well. If you think about it, it's probably THE MOST if not A VERY effective setup, and efficient. If you've got a 2-man-cap game going then it's literally 10% or less of your team to cover 3 objectives.
Sinjar, obviously to setup on A lay down machine gun fire and sniper coverage (3-4 guys) on the hill while everyone else (minus two, more on this later) gets in A fast, and hugs the RIGHT SIDE. The reason for this is it tricks the insurgents a little bit because they toss their nades and look to the left side (from marine angle) and don't see a rush. They usually suspect that MORE of the marines are working delta/firing on the hill.. the machine gunners and snipers need to be efficient in suppressing almost ALL of the hill-line or this won't work. You send the final two guys up the stairs at the same time to cover anyone flanking from delta, and watch the push on the hill behind the insurgents. On insurgents I like to run down a and get as many as i can tossing nades and muck, then when we lose A I usually sit back at the end of the double wall bottom one and pick people off like mad. I can cover the entire street and the double wall by myself in a 16 man game

Baghdad is a tricky one. You really need to get in C quick as both teams and just toss the nades and work that RPG, although they are pretty easy targets

Once you lose/get C fallback/push to next objective. Don't ever try recapturing (unless you are 100% sure, communicate) otherwise you'll leave yourself two positions down becaue the other team capped your next obj before you could retake the lost one! When taking E as marines, send two guys enroute down their spawn to the back way of E, it's a little cheap (but I do it in a way to avoid fire-hence detection-from their spawn, pretty sneaky) but it's really part of the battle..
enough for now.