Interesting.
Well in simple case I consider appearance first. The overall design of the character is what makes the character noticable. But it is really dependant on what I'm doing when a character idea hits me. For example Lix started off with her semblance, I was playing a game of Smite, the class role I got was Mage, and things basically lead on there.
As for personality implemented, plenty actually. Little tidbits of observation from friends shape some characters. But I know myself best and I do put in some real personality. Lix's inability to decide quicky stems from my childhood personality.