To be successful on the AP Exam - you must study and review outside of the classroom! If you just come to class and listen in class that is not enough! You must work outside of the classroom! Here is a great website that will help you prepare for the Exam in May - hippocampus.org.
Once you get there = you must find AP US History. They have many subjects they offer help in - so just in case here is the link to the History page:
On there they have every topic imagined from Colonial History to Modern History. What is great is they have a video that is just a brief overview, but the text is also included. So if you need to review anything - this is a great place to start!