Not bad really, just remember for inking use a kneadable eraser to lift off excess pencil marks and keep you lines clean. As for the expressions themselves, they look fine, I'm just starting on expressions myself, Nyte-Happy-Color in my submissions was one of the first I did an expression for (Which was only a few weeks ago). You're definately on the right track. My only suggestion would be if you're unsure of an expression, just look at some of the art here on FA or over on Deviant Art to give you ideas. Of course, try to keep in mind, we all have different styles, so stick to whats comfortable, after all, if "YOU" like it, it really doesn't matter what we think. Art is, after all, a matter of opinion. :)

Thanks for the advice! Yeah I definitely need to work on cleaning these sketches up after I'm satisfied with the form. I do like how they turned out, though I feel like I need help on some of the more technical aspects of this kind if stuff.