@ Uber_Soldat
Play against the easiest bots offline until u can take out like 6 of em in any gun battle easily, then up the difficulty one,
Try using weapons that are full automatic, that way u can just spray till the emeny r dead, or take out a bunch of em
Lean around corners (especially indoors) to check to see if any1 is in the next room
Walk around with your sights up, but aiming downwards at the ground, that way u can see over your rifle, with only having to bring your rifle up to shoot the bad guys (much quicker)
Carry 2 Frag grenades to clear rooms that have multiple enemies in them, better to do that then to run in shooting n plrobably get gunned down in the process
Try the M4a1 with the Reflex Sight and like 7 mags, on full auto its plenty of gun for Close and indoor combat, and when taking the time to aim, is quite useful out to 150m, remember, if a gun ain't right for you take it out of your loadout, and try something else
Keep up the practice till u get it right, if something don't work, try something else, if u keep dying in a certain area, avoid it and find another route to go around
Persist, keep up the practice, and neva give up, u'll get the hang of it already, i've been doing this for over a year, its hard at first , but when u get used to it , u'll neva stop playing