GustavoM your name sounds familiar, did you play Planetside? I was (technically still am) in one of the leetfits and we would have some of the aim gods try to share their knowledge and it boiled down to something similar. Don’t tense your hand, prioritize a relaxed posture, and learn your mouse grip (try them all out!). I’ve heard OSU is very good for those that want to improve their hand eye coordination (and get comfortable with their mouse). I’ve also heard of using spacebar to shoot but only when you want to isolate aim from shooting. But you should train both together as well.