I like to think I simpilise it in my head, people have their own methods of sketching a rough proportionate character, the only way to learn is to do. make mistakes, discover how you're going wrong and how to improve. How advanced you want to go with the anatomy is up to you as long as it is in proportion I guess.. Looking at your latest pixel I got the impression you wanted something a bit more abstract, exagerated features, large arms etc..