/ic/ - Artwork/Critique

>>5041142
Aside from the lasso option OP pointed out, you can use actual brush strokes.
Use as many separate layers as you need. Rule of thumb: do not ever paint different textures on the same layer, in case you need to touch up the color of a texture in particular without affecting the rest of the picture.
You can add shading by painting with a darker color, or using layers (adjust opacity as needed). You can use a multiply layer to get more vibrant shadows, or use a soft black brush on a soft light layer for less saturated dark tones.
For highlights, I usually rely on one or several soft light layers with a pale yellow/orange-ish soft brush. White or pastel blue for cold lighting. Some people use white on an overlay layer.
I recommend finding a couple generic brushes you really like for coloring. You can stick to the normal round brush but it's nice to work with something you really like. I'm a fan of oil brushes myself.
Also you'll want some texture brushes to make coloring easier. Having something like a freckle / multiple dots brush, a scar / scrapes brush and a couple random splashes / damage brushes can be really neat to make a texture feel more alive.