One way that works for me if I'm not firing on all cylinders is to just plain memorize. Memorize a paragraph size of material. Get a blank sheet of paper, put the rest away from your eyes. Now reproduce that paragraph verbatim. If you can't, go back and memorize half of it. Put it away, get your blank paper and write it down verbatim. Once you are able to do that, do the other half. When you've done the second half, immediately turn your sheet over to the reverse blank side and try to write down the first half again. Do the the second half right after that. Then go get a drink of water, take a breather for 10, then come back and first thing, sit down and reproduce that paragraph again, without looking. If you can't get it all, start the process over until you can.
I know there's more to it than just memorizing, but first things first. Get it into your head so it's available on exams. Keep trying to recall what you've memorized, write it down cold, but let more and more time elapse before you try doing it again. First break, do ten minutes. If you can get it all down without looking, go to something else for 30 minutes. Then try to bring that one paragraph all back again. If you can, next time don't come back to it for 45 minutes. If you can reproduce the paragraph of material after 45 minutes away from it, wait an hour next time. Then wait two hours. Pretty soon it'll be in your brain so deep that you can go a day or two and still be able to recall it without having thought of it in the meantime. It's a lot of work, but it's what I had to do. I ended up with a 3.003 avg after the comp. I remember that they grade VERY generously on the comp, but I didn't care.
Your first concern is getting that GPA up, and it doesn't matter how. At NPTU you'll learn how to use the knowledge you have in a more practical way, but for now it's all about test taking.