What do you think I can improve on my graphite drawing?

It's alright, you didn't make it your own. In order to be an exceptional artist you need to take a subject whether it's from a photograph or life and manipulate it so it's not just copying a random picture. It helps when you have some sort of attachment with your piece, but when you take pictures off of the Internet your not really makIng your work resemble you. It helps if you take your own picutres. The drawing could also be darker. You need to really push your darks and make your lights lighter. I know that making your picture darker might be scary but you have to do it if you want it to have the wow factor. Don't be afraid to make the branches and leaves a little bit different from the picture. So some artistic freedom, dont be so structured with your work. Hope I helped!