Wow, these are really great!
My tip would be to remember that hair sticks up off the head... in a lot of these it looks plastered flat XD
[URL="http://www.howtodrawmanga.com/howtodraw/jdillon/hair2.htm]This is a good explanation, and how to remedy this XD[/URL]
Keep on practicing, and you must show us more of these when you do~