I agree with Seiseki, if you're going for something cartoony, stay away from all the extra details, and keep it readable and simple.
If you're going for something realistic now, and even if you're going for something cartoony, study some anatomy, even just some simple stuff. It's always a good thing to have some basis on what you're doing when creating a character (such as prominent areas in the body), and anatomy is a great way to develop that.
Right now, if you're going for an isometric sprite, the chest, and shoulders are misaligned (the hands too, but just slightly).