You came to a good place to learn how to improve your studies. Getting a degree of any kind requires all sorts of information to be retained and there are many different types of mnemonic techniques that can assist you in recalling that info. If it’s theology you want, I’ve had some experience with that having attended a seminary and then teaching at an undergraduate school of another seminary.
My first recommendation would be to find a way to memorize verbatim many of the scriptures of your favorite translation. Then you have all sorts of lists of kings, prophets, and other important people. Concepts will be important to convert to keywords that create images and can be associated with what you need. Foreign language words are popular to memorize. Authors’ names and people’s faces are good to know also. And if you get good, you might even consider memorizing as you hear lectures spoken or the reverse of having a memorized outline which you use for a speech yourself. There’s several techniques for each of these types of information.
Since you’re new, check out the basics here on the site under Resources, especially the free PDF on memory techniques. Use the search function to look for specifics or just start a new topic yourself and ask away! And most of all, start trying one technique and see how it works for you. Get good at it and then learn another.
Doug