Hi, i thought i posted this before but here it is, one of the ways of how i do coloring. This is a more simpler approach of coloring if i need to finish it fast.
Did it on photoshop.
1. Do some sketches. I don’t usually refine the lineart if i aim to paint over the lineart. Also the sketches is very messy done for me but during the painting it will be refined along the way.
2. I started filling in under it with grey tone which after that i apply with light source and shadows. There is 2 layers as of now, the sketch layer and the paint layer below it.
3. Usually i flatten all the painting together and then i put color on it by playing with Color Balance(ctrl+B),Hue/saturation (Ctrl+U) and curves (Ctrl+M).
You may want to adjust the color for the whole painting first and later for the smaller parts using lasso and selecting on parts where you want the color to be different. It is pretty much the same concept with start painting the big picture first and the small details last.
4. After i got the basic color i wanted, i finally start to refine the drawings, painting over lineart, skin details, creases, hairs ,etc2. Around this time, i make the character painting 1 layer and another layer below it for background. I kinda hate too much layers, and besides painting 1 character on a single layer can make color adjustments easier.
5. Added some backgrounds and more touchups. So its done. For this method, usually the painting done in 40 minutes to 1 hour (depends on the details needed actually)
notes: There are other coloring styles i used for other styles like cartoon style where i don’t throw away the lineart. That would be on another tutorial i guess. Also, sorry for my bad english :D