If I had any liable information, I would give it to you. However, I struggle with this myself, so the most I can say is “I sympathize with you.” Which I do. I suppose the best help I can give is, remind yourself that you are not that character, and the character is not you. It’s a totally different person, so think of them as a friend and say, “what would so-and-so do?” You could always hold a “conversation” with them, asking them questions and answering, and trying to find out more of how they react to certain things versus the way you do. You could give a scenario, then wright next to it what you would do, then what so-and-so would do.
"You have to go out, but you don't have to come back." ~ The Surfmen's Motto