First, know that the first month, maybe longer, will probably feel pretty terrible. You might feel unsure of yourself, wonder what you got yourself into, and start thinking that there is no way at all you can do this. Those feelings are normal, and if you start off with strong study habits, and ask for help when you need it, you'll feel a lot better soon enough.
Definitely start doing NCLEX questions from the very start. Get a few different books (previous version is fine to save money, just try to stay within 1-2 versions of the current one). You will find that you prefer some over others- I have 5 or 6 that I go between, depending on the topic. When you do the questions, read ALL the rationales, not just the ones you get wrong!
Check out some Youtube videos about how to take nursing tests. They are very different from tests in other subjects, and going in with strong test taking strategies will set you ahead. There's one called "Test taking tips for nursing students" by Megan McClintock, and Nurse Nacole has some great ones on her channel as well. Watch those, along with the study tips videos.
Never ever EVER change an answer unless you know exactly WHY the answer you first put is wrong, and why the new answer is right. Even then, don't change it. Don't even bring an eraser to the exam.
Study the material before you go to the class that is covering it. My program is already structured this way, but even if yours isn't, you need to be familiar with what the teachers are talking about before lecture. Read, take notes, and look over the powerpoint if they give them to you, before the lecture. In lecture take notes on the powerpoint, and then after class go back to the book and go over the material again that your teacher focused on. Then start doing all your NCLEX questions on the topic, which will help you see if you need to go back over anything a third time.
In terms of reading the book- you don't have to read every page. In fact, you probably wouldn't have time even if you wanted to. By knowing how to focus on what you need to know, you'll spend less time reading, and retain more of the info. Nurse Nacole has a great video on her youtube about how to read a textbook. When you do your pre-class reading, use her method. Then after class you can go back through it and go a little more in depth on the things your instructor focused on, and anything that you don't feel comfortable with.
Go in with a STRONG knowledge of A&P. Could you get an A on a final exam in both A&P 1 and 2 right now? If no, I would really recommend learning that material before starting. They don't teach A&P, you're just expected to have that foundation knowledge. Without it, you will be very lost on so many different things- it is really the basis for understanding assessments, interventions and evaluations, disease processes, med actions, etc.
And finally, the biggest thing is simply putting in the time it takes to succeed. There's a lot that you need to learn in a short period of time, and unlike a lot of other subjects, simply memorizing facts won't be enough. You do need to memorize a lot of facts, but you also need to understand what they all mean, how they relate to each other, and how to apply that knowledge to caring for the patient. You can't cram for the exams. You might pass that specific exam, but the material is cumulative, so if you don't retain it, it will catch up with you. You might fail future exams, or fail clinical because you aren't prepared with the knowledge you need. Even if you manage to make it through all that, you still need to pass the NCLEX, and that covers everything. There are a few genius students out there that can look at the material once and retain and apply it, but if that's not you (it definitely isn't me!), prepare to put in a ton of time outside of class to be successful.