I tend to start from the torso, because for me, that tends to define where the centre of gravity is and a lot of the tension or relaxation of a pose, but I do it all very loosely at first, especially if I know there will be a bunch of characters in an illo or scene, because I want to keep everyone in proportion and make sure their poses actually work together as a composition.
Generally though, I focus most on the bodyparts that define the "energy" of the pose first, and I just kinda... draw it? I don't have a rigid method now. I used to draw with more defined volumes, but I think it's one of those things you need to do less and less over time as with practice, your understanding of the volumes of the body becomes more instinctive.