Focus a teeny bit less on the individual data points/facts/values and pay a lot closer attention to nursing process and critical thinking. You're aiming to have a better sense of the big picture. There's a reason for that.
With the increase in SATA questions to assess your ability to think critically, that's what should guide your whole thinking process. Sure, you need to know what a normal (or roughly normal) range for WBC or whatnot is. And in regular work --AND in NCLEX-- it's even more important to be able to recognize an abnormal value and think about what to do about it, including, perhaps "Get more information." Or to recognize a normal finding and look for other information to identify a problem (including deciding if there even is one).
Whatever else you do read, make sure it gives you the rationales for why the wrong choices are wrong as well as the right ones, right. This is where most people fall down-- they pick an answer that is factually true but is not the best answer for the situation as it would be assessed by a good RN.
NCLEX items are developed in part from knowing what errors new grads make and how. They tend to be of two kinds: inadequate information, and lack of knowledge (these are not the same thing). The goal of NCLEX is to pass candidates who will be acceptably SAFE in practice as NURSES. So-- they want to know what the prudent NURSE will do.
1) When confronted c 4 answers, you can usually discard 2 out of hand. Of the remaining two,
-- always choose the answer that (in priority order) makes the patient safer or gets you more information. "Can you tell me more about that?" "What do you know about your medication?" "What was the patient's lab result?"
-- NEVER choose the answer that has you turf the situation to another discipline-- chaplain, dietary, MD, social work, etc. It's often tempting, but they want to know about what the NURSE would do. See "always..." above.
2) "Safer" might mean airway, breathing, circulation; it might mean pull the bed out of the room and away from the fire; it might mean pressure ulcer prevention; or improving nutrition; or teaching about loose scatter rugs ... Keep your mind open. It might also mean "Headed down a better pathway to health." For example, while telling a battered woman who has chosen not to leave her partner that "studies show that he will do it again" is factually true (and that's why this wrong answer is often chosen), the better answer is to acknowledge that you hear her choice to stay and say "now let's think of a plan to keep you safe." This doesn't turn her off from listening to you, so she will trust you, acknowledges her right to choose, and helps her along a path to better safety.
3) Read carefully. If they ask you for a nursing intervention answer, they aren't asking for an associated task or action which requires a physician plan of care. So in a scenario involving a medication, the answer would NOT be to hang the IV, regulate it, or chart it; it would not be to observe for complications. It WOULD be to assess pt knowledge of the med/tx plan and derive an appropriate patient teaching plan. Only that last one is nursing-independent and a nursing intervention.
Again, they want NURSING here.
4) The day before the test, do not study. Research shows that your brain does not retain crap you stuff into it at the last minute-- musicians learning a new piece play the first part on Monday, the second part on Tuesday, and the third part on Weds. Then they do something else entirely on Thursday; meanwhile, behind the scenes, the brain is organizing the new info into familiar cubbyholes already stuffed with music, putting it ready for easy access. On Friday, the whole piece works much better.
What this translates for in test-taking land is this: The day before the test, you go to a museum or a concert, go take a hike, read a trashy novel, make a ragout, do something else entirely. Take a small glass of wine, soak in a nice hot bath in a darkened tub with a few candles on the sink, get a nice night's sleep.
5) On your way out the door in the morning, open the refrigerator door and read the mayonnaise jar label. Do what it says: Keep cool, do not freeze. Have fun, you almost-nurse, you!