Does your pencil weigh more than 20 pounds or something? Really, easy on the presure you put on your pencil, you damaged your paper there, making the erasing proces impossible to fully work..
There is absolutely no structure in your drawing, lose components put together, the character is missing attitude, anatomy, charisma, it's a flat, proportionless bag of lines that somewhat looks like a humanoid..
Lay down on the shading to.. Ofcourse, it's nice to have some accents of muscle and relief, but don't overdo it.. You don't have a lightsource in that drawing, you just added shadowlines where you think shadowlines could work, but you forgot the fact that a lightsource defines the shading, if the lightsouce is placed on the left, then all the highlighted areas on the body will be on the left, and all the shaded areas will be on the right..
Tips:
- Learn the basics of structure and anatomy, there are alot of great books out there, or if you don't want books, go out with lot's of paper and draw real life people (I always draw people on the train on the way to my girlfriend).
- Learn to control your pencil, you have to learn to control your presure, never, ever damage your paper.. Don't hold pencils like you hold pens, a pencil should be placed losely in your hand so you have full control of the presure you put on it..
- Grab a pumpkin, grab a spotlight (or anything else that focuses light on one area), place the pumpkin on a table, let the spotlight shine on your pumpkin, study the shading, recreate the shading on a piece of paper.
In the end, you have potential if you keep trying, follow these tips, there's alot more to drawing that just a pencil and a psheet of paper.