You'll have to deal with a large amount of medical information, which is often presented to you simultaneously. Reams of text can be confusing and discouraging, so try to approach medical books and your notes in an organized manner and break down the material into manageable stages. You might try calculating how much you've got to read by a certain deadline and then work out how many pages you should do each day, or else pick one topic to read about each time you study.
Remember that any medical professionals you're assigned to have years of experience, and you can learn from these people in the same way you can when studying medical texts. You're there to help nurses you're shadowing, so get involved, even if something is new to you and thus intimidating. Not only will the professional think better of you, but you'll learn things faster by being pro-active and being attentive of any advice you're given.
Experience in a clinical environment, with real patients, is a suitable way to supplement your book study and thus enhance your learning. You'll likely be on placement as part of your nursing course, but you might be able to find out about additional opportunities in your local area where you can get involved. Consider lending a hand at outreach organizations or nearby clinics; the experience you pick up there will help you learn real-world nursing skills.
Many students use index cards to help them learn information, and nursing students should certainly consider this revision technique. On each card, you can write a different disease or type of test, for example, and then reference these study aids when it comes to revising each topic. File the index cards away for later use, too.
You can't expect to digest all of the information you're told in nursing lectures and in clinic, but the chances are that if you miss something, a classmate may have picked up on it instead. A useful way of ensuring that you don't get behind is to study and revise topics with fellow nursing students; each individual can add their own knowledge, with the result being that all members of the group benefit.