I prefer mechanical pencils. You can get any size lead, and you can get leads from 8B to 6H. The only difference is that you don't have to sharpen them all the time like you do with regular pencils.
Just slow down and focus on tightening up your strokes. Practice shading to show 3D shape. Practice on drawing a sphere until you can draw one that actually looks round. Here's a pretty good explanation of lighting/shading....
http://www.artinstructionblog.com/drawing-lesson-a-theory-of-light-and-shadeYour drawing is very good. The only thing about it is the shading. It's very hard to allow yourself to spend lots of time on the "boring" things like hair, legs, grass, etc. It's really fun to draw the antlers, and then it's easy to rush the rest so you can call it "done". If you spend as much time on the small details of the boring things as you do on the antlers, it will make a huge difference. Patience is the hardest part for me.