ahhhh thanks for using my tutorial!!
Firstly, I know how hard it is to colour with a mouse (Trust me, I've been there lol) but one of the things I think you could work on is the way you coloured the hair; I notice that the orange and blue is sort of randomly placed and isn't really tallying with the shadows and highlights of hair. This can't really be explained, but you'll get it with enough practice (sometimes it helps to stare at other artist's artworks to see how they draw/colour).
A general guide is that the hair's shadows in anime colouring usually originate around the top of the head, with additional shadows from the loose strands; The highlights usually form an even ring around the head (unless there is a lightsource) Just keep in mind that hair isn't one mass, it's a lot if individual strands that are simplified into locks; it shouldnt be coloured like how you would colour a shirt or the skin.
The other thing is the anatomy, while it is difficult to learn, should be studied as soon as possible, if not you'll regret it later!!! You don't have to take courses or whatever but just try drawing people from life, or if that makes you uncomfortable there are websites like posemaniacs to help you out! In this picture the hand with the ribbon looks detatched from the body, and the forearm is too short. Also there is a specific structure to the ear, you can try looking at references or tutorials!!
Sorry for having such an intimidating wall of text, but I really hope my critique helos you!!