Get a good NCLEX review book and do the questions. Saunders and Kaplan are good ones. They come with a CD and hundreds of practice questions. The more you practice the questions, the better you'll get at taking those tests, which are generally NCLEX style.
You can study all day long and still fail those tests if you don't know how to approach those questions.
Another bonus is that the practice questions include a rationale which helps shed some light on why you might have gotten the question wrong.
Here's another tip: if you're taking a test, don't overthink the question. Go with what you know. Don't analyze it too much, and for God Sakes, don't change your answer unless you're absolutely certain it's wrong. You'll confuse yourself and end up changing the answer when you had it right in the first place. Also, don't read into the questions. Don't sit there and say to yourself, "Well, Option B would be correct if such and such were happening, but then again, Option A would be correct if this happened."..... Just read the question, making note of the stem, and answer it. Don't over-analyze.
While reading your text, which by the way you should do before lecture, focus on the manifestations of each disease process and take notes on how each disease is similar/different from other diseases within that section. Don't just memorize the signs and symptoms --- try to understand WHY. EX: CHF --- left sided vs. right sided --- signs and symptoms are different. WHY? Try to make it make sense to you.
Also, focus on the nursing interventions for each section. EX: Take note of the fact that the interventions can be similar for ALL respiratory processes. But for certain things, the interventions might be different. Take note of the exceptions.
If the question asks you what you would do FIRST, remember your ABC's and Assessment. Always go with your ABC's. Airway, Breathing, Circulation. These are your PRIORITIES. Choose your answers based on these priorities.
Always ASSESS your patient first and foremost. Don't check the IV machine, call the doctor, evaluate what the nurse did last night, etc. ---- ASSESS FIRST. Think about what you can do for the patient before you leave the room. Simple interventions that can be performed immediately are usually right. "What can I do for this patient right away?" "What can I do to assess this patient right away?"
Hope this helps.