One of the best things you can do to improve your memory and keep your brain healthier for longer is to learn a language. Whether this is formally with classes or on your own for fun with apps like duolingo – even a little bit is really helpful, especially as you get older. I know someone that didn’t want to commit to completely learning a language so just stuck post-it notes all over their house with the swedish words for whatever they were stuck on e.g. a post-it on the fridge said “kylskåp” and one on the cupboard said “skåp”. When he knew all of those he switched the post-it notes to a different language.
Learning a language is just one way to improve your memory on a larger scale (any new skill will help e.g. learning to cook or play a musical instrument). If you’re trying to remember specific information for exams for example one of the best things you can do to check your own understanding is try to teach the information to somebody else.