It sounds like you have a great plan there. Increasing the study time but with a few breaks worked in so as not to reach brain overload, coupled with prayer and reliance on Our Lady, the saints and your angel, should work wonders. Ask your angel for just a smidgeon of his incredible knowledge and thank God for your angel.
Also, hopefully you have a willing teacher who will be glad to help in any way he/she can. I always told my kids to study hard, write questions down that you really don't understand to ask the teacher, and last but not least, when you've tried everything else first: Ask your teacher for extra credit. Of course, extra credit should only be requested after thorough study time has been employed and all assignments turned in. It's a shame when a student loses points by not getting assignments in on time. Organization is key.
You're in my prayers.