Well, to start, the anatomy isn't good. The body doesn't flow naturally if you get what I mean. I'm not sure where the other leg went, and the head is drawn awkwardly as well as the face. The coloring isn't blended very well and the sword is in an awkward place. Practice makes perfect!
I'd definitely recommend you look into practicing anatomy. Preferably real human anatomy, avoid anime tutorials! Your proportions are good, but certain parts are sitting awkwardly and don't line up well together and the right leg seems to have vanished.
Sitting poses are tough, though! So it's a good attempt!