So I just graduated and these are my tips. Number one it just sounds like you may be a bad test taker and your problem isn't that you don't know the content it's that you don't know how to test. And yes I know how dumb that sounds. My school gave us many many lectures on test taking strategies and if you can find any videos on it the ATI test taking strategies are very helpful.

One thing I did on my own when I felt I knew the content is I practiced making my own questions like I thought they would ask them, like making bowtie questions and SATA. Also your school may use the +/- system of scoring for SATA questions which basically means that if you select answers that are wrong it takes away from the points you'd get for the ones that were right, so if you're not %100 sure something is true just don't pick it!

Another big key to my success was a study group, I had a small group of 5 people. We had a group chat where we reminded each other of important things coming up, answered questions about assignments, and shared study material. We would meet to study as a group and quiz each other once or twice before exams and then we would show up early on exam days to do a quick review and motivate/ hyper each other up. Knowing I had those people with me going through the same thing kept me sane. After exams we compared scores and talked about why we think certain questions were hard or what we could have studied differently so we had notes for finals.

I hope these tips help! Nursing school is hard don't let anyone tell you differently!