You've probably already tried reward systems and plenty of punishments. Those don't really work to address the distractions your child faces. You need strategies to help your child focus.
Based on my years both as a classroom teacher and as a homeschool mom, I have some ideas to reduce distractions. If one thing doesn't work, don't give up. Try something else. And remember that some children find best results with a combination of aids.
By all means get feedback from your child. Help her to identify her attention problem and its causes. Is it visual cues, auditory elements, or her vivid imagination that distract her the most? What would help her reduce those distractions? Show her this article and see if she likes any of the ideas here. Giving her ownership in the process demonstrates her responsibility to pay attention and your willingness to help her.