Wonderfull!
Man you have a great talent!
...was joking
Well if you are looking for improvement I think you can find many guieds on the web about 'the basics of how to draw human body'...
...Or how to start drawing pictures in isometric then later in perspective view.
And about the lines. I think you should forget about these hard 'hairy' outlines. Try to drive your pen/pencil light and continously repeating the line untill you find it's final shape.
+rep for the spirit and good luck
p.s.: I have a very good book with the tilte 'How to teach illustration' but it's in hungarian