First thing on my mind before any hand is my stack size, then others stack sizes. It's always there and my range is dependent on my stack size. And from there, in order, cards I'm dealt, my position, action before me, my table image, and whatever history I can dig up from the people that are left to act.
That's usually my train of thought, I'd like to put my table image as a higher priority in the thinking process cause it should allow me to widen or tighten my range but I haven't been successful as of yet. Working on it though.