First, learn when and how to use different firing positions: prone, sitting kneeling and standing. the higher up you are, the less supported your arms will be, the more tired they'll become. the link provides a brief explanation and a picture.



Second, in marksmanship, you're often taught to take deep breaths and hold then fire the weapon. don't do that, don't hold your breath. in non stressful environments, it does help as you regulate your breath and can repeat the procedure as required. that's not what we're doing here. When you're trying to line up a shot when stressed, you'll hold for too long and start shaking.

instead, breathe normally and fire the weapon at the same place in your breath (empty is a good goto). this will make you consistent, boosting your accuracy.



Third, and this one is weird at first, use your body's natural point of aim (or Nat-PoA). your body wants to line itself up a specific way. use this to your advantage. go to the range and aim at a target. close your eyes, count to 3 and open them up again. that's where your body wants to go. slide your feet so that the weapon goes back on target. this way, your body's alignment isn't disturbed too much and it'll be easier to aim.

do this a couple times you you'll start to learn what your nat PoA is and can (roughly) get into position as required. (you'll be a lot less shaky if you body doesn't have to hold a weird position).



Four, you don't have to take your eyes off target to rack the weapon. practice this at the solo range. if you don't have to take your eyes off target, you'll have an easier time taking people down.



Five, the scopes have "range finders" in them. these are called stadia lines. you can use them for many things, including ranging (guestimating target distance). go to the solo range and aim at the targets. you can figure out what distance the head/half body/full body by aiming at varyingly distant targets. this will help you with bullet drop, and will help you with callouts for team mates.



Six, while we're on scopes, if you see black lines around you scope, your eye relief is off. the black lines tell you which direction to move. if they're all around, you're too close or too far to/from the scope.



Seven, use the fleshy nubby part of your finger to SQUEEZE the trigger. don't pull, that'll throw the ouchy end off target. it takes a bit of getting used to, so practice at the range solo.



Eight, aim for center of mass. don't go for headshots. yes, head shots will kill, but you'll have an easier time scoring torso shots than headshots.



Nine, make your callouts. your job is to give situational awareness to your teammates. as is their's, you.



Last, and this will sound counter intuitive, take your damn time. unless you're trying to lead the target, you can often wait them out. most people will go to cover and stay there until the firefight is done. if you haven't dropped them before hand, wait until they poke their heads up.

if you have more specific questions, please let me know.

*Bonus round: Box breathing will help you a lot (like in life in general too). this regulates your brain's oxygen intake, stops you from overthinking, and calms you down. very effective in stressful situations.

Breath in for 3 seconds (site says 4, but 3 works for me),

hold for 3,

breathe out for 3,

hold for 3.

This will effectively negate my second point, without actually doing so. you'll "hold your breath", but not long enough to start the shakes. you can fire the weapon during either "hold" phases, but I suggest empty phase, as if you're messing it up, empty will still be a consistent spot.

Edit: grammar, words, and coffee intake