First time working with a model: Tell me what you think about my photos?

I'm an amateur. I'm 16 and i don't have any professional equipment apart from my Nikon D90.
I got my friend to model for me, this is the first time I'm working with a model.

Please give me some constructive criticism and how I can improve.

Your use of light is very interesting and adds a lot to the images. Keep exploring and I'm sure by the time you are 18, you will not only have a following, but a good client base as well.

Your ability to direct a model is something most people do not get. You've got it

1 or 2 criticisms:

1) avoid the over processing… Get the photos technically right, so you know what you are doing with composition, angle, light, etc… Once you can shoot a model without thinking about it, and getting it right every time, THEN work on the "creativity"…

2) use plain backgrounds or "portrait lenses", so the background doesn't become too much of a distraction…

3) look at other portrait photographers, on flickr, and see what they do with their models… Make notes about what they do and see if you can emulate.

other than that… Good first try…