In this technique, the sketch lines are reduced in opacity and are eventually painted over or incorporated into the final image. I took these screenshots from the photoshop document to show how little the sketch lines are visible right before the direct paint layer is applied. There's very little difference in visibility at this point, and the direct paint layer polishes up any other visible lines. This is a cool character! I like how you executed the rim lighting.

Lovely work! This depends more on the style you want to go for, but for something more painterly, I would recommend lowering the opacity for the linework and using the values you already laid down to describe the form instead. Especially with the silhouette outline, the contrast between the dark background and lighter skin tones alone will allow the form to read on its own, and pushing the background to be a bit darker can help make it even clearer. Using shadows to define edges can also be of great help. It's already looking very good, so this depends on the final style you want to achieve -- keep up the great work :)

I agree, I'm seeing the lightest lights in the legs and on the back. Decreasing the value range in those areas can help draw the eye to the areas that you want to be the focal point. I love the shapes in this, great work!