Looks like you're working neither in painterly style or line-art.
Its easier to follow one method or the other.
If you choose line-art, draw 1 pixel black outlines, then add colour afterwards.
Prefer painterly style myself.
This means I don't worry too much about the perfect shapes so early on.
At this point I find defining a primary light source and adding just 1 or 2 shades useful for sculpting shapes that feel right.