Some things seem kinda paper-like; the guy's legs especially. His belt is pretty straight... It should kinda "wrap" around his body more to show depth. You can also shade his legs a bit to help with that. His legs also seem... I dunno. Maybe his thighs aren't thick enough. Perhaps his knees are too high, though it's hard to tell where his knees are. I generally try to keep the ears closer to the horizontal center of the head on side views (better explanation here:
http://cloudflash.net/arttips.php ). The male's hands could also be bigger. The hand should be big enough to cover the face or something like that.
Also be careful about the ear shape. Just Google something like "human ears" in images and hopefully there would be some side views... I think the ear shape you're drawing is a bit off (unless you meant for them to be some non-human race or something).
I think the ear thing is the main problem, and it threw you off with the faces and hair/head shape. There are some good points, but they're mixed in with some of the bad points, so I'm not sure how to describe them well. The bodies look pretty decent overall. The guy looks very tall, but I assume that's intended. Keep up the good work.