Tits completely dominated your composition
wow, she really have big breasts, but I must say I don't really like them, they are definetly too big for such a petite body. She should generally be wider in arms, and have a wider chest, unless you wanted her to be unnaturally thin.
What I like is colorplay and the face overall, the features, such as eyes, nose and lips are looking nice together. I only would do a background a slightly darker, just to emphasize the colors.
For a sketch It's quite not bad, but nothing more.