Nice job on the foreshortening on the girl--it really looks like the viewer is gazing down at her. The guy's shirt throws this perspective off, though--it's a little too straight. If it has more of a curve, it will look more like you're looking down on him as well. Perspective pics like this are very difficult tod o, so I have to commend you for trying! Good job!

The coloring is pretty decent. Don't be afraid to add more highlights--you seem to have the shading down pretty well, but highlights always add to pictures.

I have a Wacom tablet too! I'm afraid to use it too much, since it is extremely different than a regular pencil or pen. My main advice is don't hold it like you hold a pencil--The best way to hold it is more straight up and down, instead of the angle most people hold pencils at. And keep practicing. :)

Good luck!