When developing OCs, I've realized I tend to figure out their history first and only then think about their personality, which means that often I only have a loose idea of who they are and nothing about their personalities is as fixed as their histories, which often leaves me with vaguely bland characters.

I'd like to be better about developing interesting characters who aren't quite as reliant on their backstory/history to prop them up. So for those who do write OCs, how do you develop their personalities? What do you start with, how do you fully flesh it out, etc?