One example is very little tbh 
Also, I haven’t see the outline so idk if - for example - eyes, that are placed a little bit too low are your mistake or is it the outline. Anyway studying anatomy is always a good choice.
What I can say about the coloring though, it’s really good! Hair is even suspiciously well done, compared to the rest! 
Don’t be afraid to use hard shadows and dark colors. Try to always think about where the light source is (heck, you can even draw a simple arrow in the corner of your art, to always be able to look at it) and apply highlights and shadows accordingly.
I’m not a master in art either, but if you ever need constructive criticism hmu! 