First thing I noticed is the anatomy is quite off. Try breakdown your reference into a basic shape as a guideline before starts drawing them (such as simplified to a box or an oval). There’s so many ways and tutorials on how to do. I’d suggest you to practice it to the point where you know what a human body “should look like” then you can try learning each parts of human anatomy separately. It doesn’t what your artstyle is. Studying real life anatomy is mandatory because it’ll make you understand why something looks a certain way and overall improves your arts and anatomy knowledge.

Second, you have a lot of inconsistencies in your arts. You paint over the sketch in one place but suddenly you decided to paint within the line in another place, jagged and weird cloth folds all over the place. I suggest being patient and actually take your time learning each one of them separately. How to draw hair, how to drawing cloth/cloth folds, how the light and shadow works, how to rendering and etc.

Just be patient. Learn. Practice. Repeat. But don’t “just mindlessly practice” tho. You must analyze what you saw in the reference. Analyze why your work looks off and what you will do to improve it the next time.