It sounds as if this young lady could benefit from some general social skills training. Teaching her and having her practice skills such as following instructions, listening to others, and appropriately interrupting would be beneficial to improving her behavior at school. Discuss with her the importance of learning these skills now and in the future when she's in college or working. Remind her that along with being disruptive, her behavior probably makes it harder to make and keep friends.
Explain the steps to each skill. Give a rationale for why this skill is important. Have her repeat the steps back to you, then practice. Give her positive praise for practicing. Practice with her as often as possible and you may even consider setting up a reward schedule for getting positive reports from her teachers on her improved behavior.
Here is an example:
Skill to practice: Following instructions
Steps to follow: 1. Look at the Person 2. Say "Ok" 3. Do the Task 4. Check back when the task is done.
Rationale: "It's important to follow instructions immediately when you are asked, because when you do, you are more likely to have time to do other things you want to do."
Practice: (Have her practice following instructions)
Give positive praise: "You did a great job following instructions. You looked at me, said ok, then checked back when you were done with the task. Great Job."
It takes time to change behavior, so be patient and give her some time to learn and practice. For more information on social skills training, visit www.boystownpress.org