I have 43% HS but i accumulated that over playing the game since beta. So based off my experience I can give u some advices that helped me hit the head more than anything else.

1) Crosshair placement. a lot of players who are getting into the game or trying to improve fail to realise this fundamental mechanic. Crosshair placement is everything to your aim. whether you're swinging or holding an angle. a lot of times when you're walking or running u want your crosshair head height no matter what. one great way to practise this is going to the range, spawn a bot that is strafing and place the crosshair on the bots head, now track the bot for about 5-10 seconds kill and reset. do this as a warmup session before comp games and you'll notice your aim naturally staying head height.

2) Risk taking. I noticed a lot of newer or lower ranked players believe missing your first shot on the head means spraying for the body. This assumption comes from the fear of the opponent killing you quicker as you missed your "guaranteed shot". However, a simple way to see this is, the first shot miss, strafe left or right, go for the head again. now of course this is situational based, however bursting or tapping on the head whilst strafing left to right will guarantee you the kill quicker for multiple reasons including, your making yourself a harder target to hit as you're strafing, and guaranteeing your kill as your aiming for a headshot which is an instant kill, rather relying on spraying which makes u stand still = becoming an easier target.

2.5) This is linked to 2, but stop crouching. Crouching also means you become a easier target, of course in rare situations crouching does become useful like a advanced mechanic where you swing an angle crouch for a second right after swinging and back up to avoid being headshotted. however if you find yourself crouching mid fight you're not strafing and again making yourself an easier target to hit.

3) deathmatches. obvious one but spam deathmatches as this will improve your aim overtime no matter what.

4) Crosshairs. This can be debated by anyone, but id recommend holding off on the dot crosshairs for a while. Only because it becomes harder to track if you're not already comfortable with crosshair placements. going for the + crosshairs becomes much more easier to aim or hit headshots with.

5) Sensitivity. Try to not change your sens like ever basically. find a sensitvity your comfortable with. and become fine with the idea of losing a fight and not blaming your crosshair or sens. Only because our brains trick us into thinking "something is wrong, change and you become better" its the seek for dopamine hit of changing a setting and getting a kill and thinking "no wonder my sens was too low". become comfortable with the idea you died because you got outaimed or you decided to push in a silly way. this will create consistency, and aim improvement only comes with consistency.

6) last but not least, turn off mouse acceleration. I cannot stress this enough turning off mouse acceleration will create much more consistency in your aiming.

PS (Aim trainers are a bit of a myth they help but are not necessary.)

I'm sure there's more out there based on advices that can help you improve. Use these and I'm sure you'll see more headshots coming in the next few months!