I would get a copy of the book your school uses for the course and start going through each system. Make sure you learn respiratory, cardiac (especially flow of blood and where blood is oxygenated and where it's not), integumentary (learn the basic functions of each part of the system and be able to identify the different parts in a microscopic image, muscular (learn all of the different muscles and what they move and how the move it), nervous system (learn about action potentials!!! They can be confusing at first, but maybe look up some youtube videos), skeletal (learn all the different major and minor bones of the body. Know what microscopic bone looks like), digestive(which organs perform which necessary functions in digestion), reproductive (know what the cells look like under a microscope and be able to identify the basic parts of the repro system.)
A&P is NOT difficult. In fact it's quite interesting. If you can learn the very BASIC elements that I listed here you should be more than fine for the course. Make sure you know what all the different tissue types are, where they are located in the body, and what they look like under a microscope. The parts that I noticed people struggled with the most and which I would review the most prior to the course:
1) action potentials (nervous system)
2) identification of tissue types under a microscope
3) knowing the different types of epithelial cells
4) bones of the skull (know them inside and out, and what all the different holes and fossas are)
5) flow through the heart and parts of the heart
Good luck! This is not the best list in fact I'll probably amend it tomorrow because I'm tired right now and there's no much more to say about the best things to know to be prepared for the course.