My girlfriend just got a tablet, as well, and I've messed around with it a little, just to get a feel for it (not much for drawing, myself - I can sketch plans, I can do rough isometric drawing, but I don't get too artsy with it). I must say, it was pretty weird trying to use the thing (she picked it up pretty quickly, though, so keep at it

) so if this is your first work, I'd say you're in pretty good shape.
If I can give any advice (taken with a grain of salt, being that I have little to no artistic or technical training pertaining to the subject at hand), I would suggest that you don't treat the pen/pad as
just a pen/pad. You still have all of the features of your chosen graphic editing program at your fingertips. Now, you just have the added benefit of being able to more naturally control your lines. Use the shape and fill tools, when appropriate, even if you're going to scribble-shade over them (I realize it's a test sketch, but I'm looking at the top bar of the banner

). Make use of the pressure sensitivity for line thickness, opacity, etc. but know when to turn it off, otherwise you'll drive yourself crazy trying to make a simple line drawing.