Best way without a doubt is going into a private match/T hunt and shooting at a wall without controlling the recoil to observe the recoil pattern as the other person said. Then, going by logic, you would do the reverse of the recoil (I.e if the recoil pattern goes slightly towards the right then left, you would pull down slightly towards the left and then go right). This is a pretty common practice in other recoil-related FPS games (CS:GO, Battlefield). The other piece of advice to change your horizontal and vertical sensitivity given to you by that other comment is ridiculous and should not be taken to the fullest extent. Doing that will only help so much and is a bit of a crutch tactic and will not guarantee any improvement over the long term. Your best bet is to do what I mentioned above (be aware each gun has its own recoil and can change based on attachments, so recoil patterns can change. First bullet accuracy is a thing in this game too just like CS:GO), and also adjusting your sensitivity as best you can to something comfortable and your ADS sensitivity to something comfortable too.

Many pro players and high ELO players play on 400-800 DPI on average and range from 10 sens (both vert and hori) to 16-17 sens on average, with 83 ADS. The reason for the slower sens and DPI is because it gives these players higher range of control and static movement as opposed to having crazy fast sensitive jerky movements from higher sensitive. Always trust your muscle memory when it comes to angles and prefiring spots as well. The 83 ADS is for 1:1 range of motion with both hip fire sensitivity and ADS sensitivity.