Good for you for wanting critisism. I, personally have learned ALOT from what others have said. First, gloss coats don't look so good on a mini unless the object glossed is water or glass. Second, when shooting the picture, have the light behind you, not the mini. Third, use a wide range of color tone (lightness and darkness) .
You have a red shirt on your mini. Start with a regular red, paint the whole shirt with it. Shade in the folds and under the arms with a red mixed with purple, brown, or blue. I dont like to shade too much with black because it is too dark and it dulls the colors. When mixing the other colors in try to keep the mix on the warm red side. For the top of the arm, shoulder, top of folds, mix in a bit of white and MABEY a bit of orange to warm it A BIT, not alot. Do the same with white. start with a coat of off white- mix with brown or yellow ochre blue or black.....your pick. (brown and yellow ochre will give the finished product a warm look and blue and black will give it a cool clean look). You want this to be VERY light in color. Use pure white for the highlights and just a TINY bit darker for the shadow areas.
That should keep you busy for a while. Go forth and conquer!!!!!!! I'd like to see what you come up with.