For me I used to be rank 1 in overwatch and what I did to improve my aim was just put a lot of hours into the game so eventually you'll memorize the hitboxes of each character just like in csgo how you remember certain walls to lineup with for the headshot, aimlabs kind of helps with flicks but it doesn't really help as people say cause there's a lot of different factors that go into different games if you know what I mean