Welcome pengi!

Well first of all, I like how you shade, with the crosshatching and all that, it adds weight to places where I'd expect to see weight. As for the practice, it doesn't matter if you've been practicing for 5 years or 5000, everyone can always use more practice.

Critique wise... your style seems to favor a small torso and larger extremities (legs, hands, head) over standard "human" proportions, as I can see it. Overall, his head seems a bit too far to his left on his body (See this, it's a bit more rotated than yours but the idea is there: http://thebacklot.mtvnimages.com/uploads/2015/03/dig-104-guyselnik.jpg?quality=0.7 ), and his left leg seems a bit odd to me, but I can't place why. Last, but not least, his pose seems a bit rigid to me. I feel like you're going for a "slumped over, feeling injured" pose, but his back is super rigid. Even if he's leaning against a hard surface, there should be some more curve in the tummy area, unless he's forcing his back flat against the wall.

It's good to have a style you're comfortable with, but knowing how bodies work in real life helps a lot when trying to convey poses in a non-realistic style. Hope to see you around, and keep drawing :)