for me i try to pick colours based on their common meanings! for my maaain oc his initial scheme was very blue heavy bc his theme was being a scholar and blue tends to be associated w intelligence and creativity, but as times gone on i’ve added purple into the mix bc it’s also associated w those things, but also with power and nobility, which he ended up being both!

Color is just a way to show particularity of your oc , it will define his environnement. Personnality is aldready set by looking the charactere without the color , you Can achieve that with shape telling or accessories that will make sens once you know the lore