Cel Shading, pt II
Trick 1: If you want a to add extra definition to a layer, you can go into the Layer Properties and set the Stroke to a width of 2 and color Black. In my case, I wanted the ribbon around the waist to be more distinct, so I put the ribbon on it's own layer and set the stroke to 2.
Trick 2: Have some extra lines you want to get rid of? That's why you have both the CM (Cartoon Mode) layer and the CML (Cartoon Mode w/ Line) layer.
This picture didn't have much I needed to get rid of, but I could have eliminated the wrinkles by the hips.
On the CML layer, simply erase the lines that you don't like. Because you have the regular, non-lined layer underneath, you don't lose any highlighting or shadow, just some of the lines. This is especially useful for images where the clothing has strange wrinkles due to morphs or posing.
Trick 3: Add more color to your images. You have a few options to add more color depth to the image without losing highlighting or shadow.
1) Duplicate the layer. With two layers, both set to Overlay, the color is much deeper without overriding the shadows too much. It can make the skin a bit yellow, in my opinion.
2) Go into the layer Properties and add a Color Overlay. With the color picker, choose the original color of the layer then lower the opacity to somewhere between 40 and 60%. This adds some color without making everything too bright.
3) Do both - use the Color Overlay as well as duplicating the layers. You may want to adjust the layer opacities, as well.
4) Mix and Match. On items like the Skirt, duplicate the layer while for subtler colors like Skin, use the Color Overlay in the layer Properties.
Trick 4: You can add more definition to the character if you add a black layer Stroke to the CM or CML layers. It will nicely outline the character.
Most important - Have Fun!