Ok so I think it's fair to say that no one wants to read a textbook, especially a physics one. Me personally, the words just kinda go in one ear and out the other. So here's my tip on how to read the textbook: Don't read the textbook.
A lot of you are probably thinking, "YES! I've been doing that all year!" Well, there's more too it. Mr Fullerton is right when he says the textbook can be very helpful, but the way I "read" the textbook is by doing the problems. Obviously you can't just open the textbook and do all the problems at once on the first day of the unit, but go through them along with the class. It gives the stuff you learn in class something to base it off of.
Now, I definitely would not go and do every single problem in the book; some of them are unnecessary or just dumb (aka unnecessary). So, since we have a magnetism text coming up, here are the problems I thought were helpful focusing on the stuff we just learned:
28.1, 28.3, 28.4, 28.6, 28.7, 28.9, 28.12, 28.13, 28.14, 29.4, 30.1
After doing these problems, I feel a lot better about this unit (not magnetism in general, just this unit). Hope this helps you and good luck on the test!!