I get bored if I spend too long on a drawing and pick out too many flaws and end up trashing it, so most of my sketches only take a half hour to an hour to do.
Here's a quick step by step on how I draw a face
1. Outline
2. Main Features
3. Basic Details
4. Charcoal Pencil for Shading
It's super simple and not too realistic, but its not hard to make a decent drawing in ten minutes if you go over the picture multiple times, each time adding another layer of features.
