Acktoo I realise legs and feet are very hard but avoiding them will only make them more difficult.
Also you may want to switch up some of your drawing materials.
Try Staedtler pencils with a neaded eraser for sketching.
Maybe get some prismacolor liners for finer lines.
For paper try Strathmore sketchbooks or drawing pads.
I tend to use the drawing pads more for sketching.
This should run you about 60 bucks all together but if you shop smart you can save some money.
Graded pencils can usually be found around drafting supplies.
Also the Dick Blick online store offers a pretty good selection of items.
Their clearance section usually has some nice things too.http://www.conceptart.org/forums/showthread.php?t=94571
And here are some free art books for you so you can educate yourself abit more on design and whatnot.