The character itself looks quite good. You will get better with practice but I don't see any evident "mistake" I would however advice to do some background, even something basic will help bring out the figure. P.S. I don't know if you were fishing for compliments, if that's the case I will mention that I think you are quite good already.
It's like a mix of Ib and Touhou. Hairstyle and dress. Nice. If you're ever planning to make a short manga or web comic, @ us!
I can only suggest dynamic lining. I suggest giving pressure points pens a try, but that’s if you have a pen. I also use iBis but sadly my iPad is incompatible with any pens... Otherwise explore with texture bc it’s really flat, their is flat shading but it doesn’t make sense? The shading in the hair doesn’t match with the skirt. Their are other way to draw clothing folds that “shading” it. Bc I can only assume the light source is coming from the front. I like the simple color palette choice and you anatomy is pretty proportional.
I actually draw this first in my paper then put it to ibispaint then tried to make it okay then colored it with the use of my fingers without using any pens so it may look a little off.
Wow, girl!!!! This is soo good!! I.......wow! I have no words....... It's awesome keep up the good work!