Typically it depends on the game and setting for me. I mostly try to play characters how I would be myself, but sometimes certain games I pick things that I feel fitthe world better.
I'm closer to being the MC's conscience or some kind of imaginary friend, which is why I make decisions based on how the MC would act, combined with my own judgment.
For example, if a decision causes the MC to get scammed, my reaction is, "Damn, WE got scammed!"
i name the characters after myself, but i try to angle for choices that lead to sex scenes i want to see. fortunately, a lot of games have walkthroughs or walkthrough mods, so i don't really need to think too hard.
I tend to play as myself or at least a character with similarities to me, both physychal and mentally, I feel more comfortable and real acting like that
To be honest, most you can change usually is the name and depending on the game some different paths... Everything else is predetermined and not dependent on your personality.