For me, it mostly comes down to what class I want them to be, but I also have a tendency to give at least some sort of a backstory for created characters--nothing remotely deep, mind you, simply "They're a young warrior who wants to become a knight" or "A noble thief who prefers to avoid fighting." From there, I generally piece together how I want them to look based on that idea.
For example, in Dragon's Dogma, I wanted my male Arisen to be a young spellcaster who wants to hone his skills and become more powerful. So obviously, I didn't make my Arisen be this towering, bulky, wall of a man. Instead, I made him young, shorter than average, have freckles and pasty skin, with long, stringy hair in a ponytail, and all around look kinda shrimpy.
Meanwhile, I saw my female Pawn as this war-hardered warrior who'd seen a lot of battles and wouldn't hesitate to cut something in half. So, naturally, I planned on making her be quite tall, very muscular, have nothing fancy done with her hair, no make-up, and bear a lot of scars. It definitely took a long time to make her compared to my Arisen (mostly because a lot of the options for a bulkier upper-body would make her chest be ridiculously wide and thick compared to her hips and legs), but I eventually came to a design I really liked.