1. Head and Face
The hair is a little hard to master, Make it very detailed
add lines to split the arms from the body. Then, add a simple shirt.
Coloring should be easy, if you dont want shading, just do original color and dont put lights and darks.
Add darks far from the light source. Add light colors near the light source. Blending colors help mix the darks to the original.
Advanced Blending: Make a lot of shades of one color (ex. Blue)
Advanced Blending: Use your opacity settings to mix the colors that are next to each other until it looks smooth.
If you can do it, it will make your art awesome.
If you master blending, you can make art like this ( I did this on Art Academy but it works on almost any program)