How can I memorise things more effiecently?

Firstly, whatever is going on, everything is going to be great and I’m confident you can overcome not just this issue but everything else.
Secondly, I believe that writing down everything you need to remember is the best way.
You can do this in the “reminders” app or on paper. If you have a planner or a bullet journal, I highly recommend to pre-plan as a “future log” or any similar action, so you can incorporate this method with the way you plan/journal.
Good luck!

I recommend searching up the SRS system online. It's a flashcard system with spaced intervals that helps you get information down in the long term. I've using it for kanji memorization and it works very well so far

I’m the worst at this at this place in my life so I go back to Illogical Association, a technique often used for memorization, at least it was in Medical Terminology. I never missed a single question thanks to that technique. Hope it works for you.

Try to relate ideas to things or people. If they are long phrases, repeat them three times each. This tip was given by a college teacher and it worked for me just fine!

Use Anki App if it matches with the things you're learning. It's absolutely genius.

Have a short review session of things you've learned at night right before heading to bed. Giving fresh information to your brain will help store it better while you're sleeping.

Always be curious of what you're learning and willing to understand it first before trying to memorise it. Some things are bothering you? Don't spend too much time trying to grasp it but just the action of trying and looking for deeper information/explanation can go a long way.

If you notice something's hard to memorise or you keep forgetting about it, try to associate it with an idea, name, object, situation or whatever else you easily remember. It may be easier for your brain to associate the difficult stuff to the new associated thing than to memorise it straight.

Also be as aware as possible when learning something that you find difficult: when possible, mix in hearing, writing, saying, doing or watching the stuff you're trying to memorise, or related stuff. That way, your brain will make more connections with that thing you're learning, so you'll retrieve the information more easily.

It's normal to forget stuff. The best way to memorise something is to forget about it because then you have to come back to it, review it, and it really is a normal thing to do.

Lastly, try to have fun and be looking forward to your study /review sessions! Mood affects your learning time quality.

If you’re telling yourself you have a bad memory then you are wrong. My memory for movie plots, musical phrases and specific numbers far outstrips my memory for names and faces. This is due to my own personal focus. When asking how better to memorise something it’s actually better to understand that the goal is not to store a catalogue of facts but to recall useful information that you regard as important. Recall is like a muscle. It must be exercised. Short term memory recall requires short term habitual recall of the information you are trying to memorise. Mnemonic tricks like using acronyms, or associating the info. with sights, music colour and smell to get all the senses involved can help make recall easier. Ultimately it’s all about repetition. By repeating an action, in this case recall of information, you tell your subconscious that this action, recalling information is important. Your subconscious will reward you by making the act more automatic. Prolonging the habit will embed the information into long term memory.

We tend to memorise events from our lives better so you should try to associate events with different parts of what you want to memorise.