In high school I didn't have to read. I could get by just studying my notes. In college you can't do that. Many tests and quizzes are based on the readings.
Before reading a chapter, I go through and look at anything in bold letters (ie. headings and definitions) so I'll know the general ideas of the chapter.
Sometimes I scan to prepare myself. I estimate the amount of time needed to cover all the material and that helps me avoid procrastinating. If my mind wanders, I'll take notes while reading.
I don't highlight everything because everything won't be on the test. I highlight the most important points in the text. When I finish a chapter, I read the summary. Finally, I skim through the chapter one final time.
Read the chapter summaries and look over the bold terms because evidently the author feels those things are the most important. Also, time yourself! Then go tell someone what you read about to make sure you understood it.
Study whatever is boring early in the day because if you study at night after a hard day, forget it, you're going to go to sleep!
Don't get stuck on specific words or specific statements you can't grasp. A good idea is to get a sense of the text as a whole. As you read, make connections with other parts of the book.
I don't sell my books back. I sometimes use them for future reference.
The more you read, the faster you'll read. You need to find something you like to read and then read more often.