Judging from the way you draw, I'm guessing you draw it pretty quick right? Also, the lines are heavy and rugged, you want it to be smooth and thin. I suggest you use another pencil instead of a regular # 2 pencil.
Start out by drawing everything as light as possible. This way if you mess up, you can erase it easily without smearing or leaving marks. Do this until you are satisfied with the drawing then gradually make it darker.
Any way, that's my $ 0.02, I'm not a pro, I'm still learning but that's my method of drawing so you might wanna take it with a grain of salt.
Edit: sweet! I inspired someone
