Kind of surprised at this question, since you obviously made it through highschool and the prereqs of college well enough to get into a BSN program, but I will contribute. I can empathize with you in that its hard to keep your mind from wandering when reading dry material, no matter how much you actually want to learn it. I find that it helps if I make it more of an exercise. So, rather than just reading straight through, I look at my notes and for the first important topic, I find the pertinent reading on that topic and write questions that I think might get asked on a test and write the answer on the back of the card. I try to make them pretty broad so I can write less. This seems to keep me occupied enough so that I can get through all the reading without zoning out (for the most part), plus I think writing questions kind of solidifies it in your brain a little more than just reading. Reading short sections at a time is less fatiguing.
You may be tempted to join study groups, but I think they are inefficient unless your class has a truly gigantic workload given to you. Its impossible not to chat when you get together with more than one other person and it can be distracting.
Do not attempt to study at home, you will accomplish twice as much if you go find a quiet corner in a library and stay away from tv, computer, and attractive coeds. Bring something to drink, all the books you will need and a snack, plus coffee if you drink it, so that you can stay there for several hours (depending on how much material you have) and get in the zone.
Most important, stay ahead of the material that you need to learn. Every week you should read the assigned readings and at least be familiar with it. That way, the weekend before the test, nothing is new to you (except perhaps for the most recent topic) and you are reviewing rather than cramming. Cramming is stressful and you've got enough stress already.
Keep in mind that that is what I do now that I am in grad school, I was not as zealous in undergrad, so you can tone it down to suit your needs. Hope that helped.