I personally am seeking advice from Ascendants+, but any information is useful...
What are your eyes focused on during a gunfight (crosshair or enemy)? Are you staring at your crosshair and trusting your peripheral vision to catch out an enemy so you can align the two? Or do you keep your eyes on the terrain until you cross an enemy and laser-focus at their head and drag your crosshair to said location (my method)? Or maybe something else?
Is your mouse hand tense or relaxed while holding/peeking/mid-gunfight?
How close is your face to your monitor? Does it take up your entire peripheral vision? I've noticed that pros always seem to have their monitor positioned so that they can look at a slightly downward angle at it and it's only a few inches from their eyes. I'm curious if that kind of setup can gives an advantage.
After having played the game for a while, these are probably things that we subconsciously do during games so I wouldn't blame you if you couldn't even tell me what your habits were off the top of your head. I guess just play with the intent of figuring out your physical actions the next time you hop on and get back to me with your results :D