1. try lowering your sensitivity. Don't think the higher it is the better you are not true! i personally play on 3 sensitivity and most pros play on the lower end 3-5.
2. when i see an enemy i usually hipfire and bring in my ads at the same time.
3. Drop shotting/ "scuf" jump shotting is also a good tactic to win more gunfights. try playing on tactical.
source- 4.2 k/d player/ 5.6 w/l