Art Midoriya Izuku

This is my first try with digital art, and since I don't have a tablet, I've had to make do with the line tool from paint tool sai.
I've also really been into Boku no Hero Academia (My Hero Academia) lately. It's a good show, and I recommend you watch it (it's about superheroes in Japan).

Spoiler: The Art

I didn't particularly want to do his left hand. He's also skewed to the left, a bit much in my opinion. I don't really know how to change that. The shading is a bit weird as well.

Original pic:

I draw everything out first since I can't draw with a mouse. I made his shirt a more teal colour because I like it more, and didn't include the kanji for his name (I also coloured the drawing because I wasn't planning to make it digital). I also tried to use "the rule of thirds" but failed.

Please tell me what you think, and what I could improve on.