Study under similar conditions as you will be tested (mimic lighting florescent/LED/Incandescent? Dim/Bright?, ideally study in the same room or in similar seats/room, sitting ofc, if you drink alcohol studying, drink for the test too - bad idea tho), ever leave a room and forget what you’re doing? This effect applies for studying too
avoid listening to music with lyrics (or anything with talking in it except study partners/TTS Textbooks etc.), significantly hampers brain efforts
Associate your studies with a scent (ie: a cologne you only use for this purpose) and have that scent on you when you are being tested, scent is primal portion of brain strongly associated with memory
be gratuitously friendly just before studying and writing a test (pay someone a compliment that makes them smile, hug a friend or willing colleague, etc…) this reduces stress and allow your brain to be less fight or flighty
similar to previous, avoid caffeine. Ideally you should be well rested for both study sessions and the test, but if you insist (I understand completely if you do trust me) use it for both per the first point.
be well hydrated for both studying and the test (don’t forget to urinate before it begins though :P)
Supplementary tips:
Ah yeah I used to get high as shit before tests to replicate the same conditions I studied in.