I like them!
The only thing I really see that you need to work on is hands. They're quite tricky, I've gotta say, I'm still working on them myself! Another thing is shading. You don't really seem to use a lot, and just to make your drawings a bit more dynamic, you might want to try.
Shading, for the most part, is easy. You just need to figure out where you want the light to be coming from. Probably the easiest thing to do would be to look at photographs or just look at your friends and see how the light hits certain features and you can use it when you draw.
You probably knew all that, but nonetheless, I hope it helped. ^_^