Man you are going to get a crap ton of practice.
By the time you get to
,your skills would have increased immensely.May I ask if you can post an art collection so we can see your overall growth (and all your quality artwork of course)?
As for the Aatrox piece,an overall good piece.I like how detailed the sword & wings are.
The left hand seems like a blob of colors that is attached to the ground.As StrawberryCocoa said,the body is pretty murky.Try adding a little more details & definitions so people can tell what's what.Also I feel the light in his sword could be a little more bright so it can stand out more.
As for the environment/background,a bit more work could be pit in overall.Unless that what you were going for or something.I understand the goal is to draw the champ,but if you're drawing backgrounds at least make sure their pretty close in quality.Try adding a few details to the ground.