I feel like a background would have added a lot. The white shirt fits well, but it looks to similar to the background, which is also white. It would have looked a little better if the shirt was a different color, but to be honest, I think it looks best white. Also, a background just adds more to the picture as a whole, not just colors.
However, the character looks very realistically drawn and well done.
Also tits.
Dear NightWayDude.
Your artworks are great(!!!),MOAR of that,I've heard that Russian fans are very impressed about your creativity,and the Universe of School-13,but i've also have heard about your lazyness (I am so damn lazy too.I NO JUDGE :P)So,about the Red Hat Girl.I've desided to join TheManOfSteal13 opinion about the breast(Also because CTRL+C ->CTRL+V is to boring for me :D).
I hope You will keep up to Inspire and impress all of your fans.
Peace.
Cool renition and yet I can't help but ask, is her shirt wet? Normally you don't see lines depicting boobage unless you put the emphasis that she is indeed wearing a wet shirt, but from the sleeves, shading, and the lack of wrinkles I can tell that's not what you were going for.
I know how hard it is to NOT make a girl look flat-chested when it comes to rendering female characters and lines don't always help. Instead, try letting the shading alone do the work.