I'm kind of methodical about it (left-brained engineer that I am). I start from a person, trace back on direct lines as far as I can. Then I start working forward from oldest ancestor, adding children. When I have added all of 1 person's children, I methodically go through each child in birth order, adding spouse and their children. When I get to the end of the first child's descendants and their spouses, I move to the next child. I usually cut off my efforts at spouses that I add, without working on their parents, siblings, etc., but have to admit that occasionally I fall down that rabbit hole.