Here's what I could see that you could work on.
-First is: Proportions!
If you hold your hand to cover over the face underneath the eye-level, it wouldn't be that bad. You can keep the right eye where it is, but the left one needs to get slightly closer and you could arc the right one more similar to the left if you want them to match. The way it is now it messes a little with the proportions.
The mouth and nose should be further up and a little longer to the right side (for us) on the face. Not by much, but it would improve the likeness of the picture.
-Second: The face itself!
While the eyes are mostly covered in the first part, the nose looks fake even for manga. It should also be aligned better with the eyes, but as it is now it looks flat and in the wrong place. You have also drawn a "granny-mouth" which looks like Sakura doesn't have any teeth. It's because of the size, squiggly lines and the weird arc, but it can easily be fixed!
The chin is to long and pointy, and the face is also a little to... slim I guess.
-Third: Anatomy!
Take a look at the part of the shoulders I circled in the spoilertag on top of this post. How can that be justified? She's a slight hunchback with a camel-syndrome and a big... thing growing out of her neck? Yeah, you would do good if you sketched up the body before you drew it.
I know I sound overly negative here, but I just want to help you get better. If you fix these mistakes, the Sakura would be much much better overall! I can tell that your hand is a little shaky and you use too much force from the get-go, but I'm much the same when I draw. I want the drawing to be done fast, and I make silly mistakes I know I can do better... that's the reason I gave up on Deviant Art, since I just posted to post, and I never really posted anything good... I suggest you take your time when you want to do fanart or draw in general, and relax, put your mind into the slight details you would have usually missed, and you'll do great! This isn't a bad drawing, far from it, but it could still be so much better! Don't rush!
Overall, good job! I hope I get to see more drawings from you! And since you're a pencil artist as well, that makes me happy!