Your lineart is looking pretty nice now. Keep it up.
On coloring: If you're having problems picking colors, there is always the eye dropper/color picker tool in GIMP/Photoshop/etc. Get a good picture of Miu/Tsubasa/whoever, and use the colors the professional illustrators are using. Do this long enough and you should start to be able to judge on your own what colors are okay for skin or clothing and what colors makes the skin too dark, etc.
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