Ok listen, it's late at night for me and I should be sleeping. However, I thought I should make a master list of study tips because that's a huge part of what I teach. Most of my students are in their first year of college, so a lot of them want both chemistry content help and help navigating college courses. All my training is about both of these. These can be applied to studying literally anything. I use these all the time in my own classes. Enjoy!
First of all, your brain only functions when your body does. It is almost never a good idea to stay up all night before a test to study, the consequences of being tired almost always outweigh any benefits of extra study time. Also, your brain needs food and water and sunlight and social connection to function. Those are important. I beg of you, eat an actual meal prior to your exams.
Your brain remembers weird stuff better than normal stuff. I come up with wacky, out-there examples because they stick better in my brain. 'BrINClHOF' is a series of letter, but 'Have No Fear Of Ice Cold Beer' is an actual, somewhat strange, sentence. It sticks better. (It's for diatomic elements btw!)
For the studying part. Use the study cycle. This has been thoroughly researched and it works. Take an hour, spend the first 5 minutes setting goals, the next 40ish minutes studying, then take 5 minutes to see if you accomplished the goals, then 5-10 minutes of a break. The break should be something relaxing, stay off social media, call a friend, take a walk, have a balanced snack, etc. Repeat as needed. The studying part of studying should be active, not passive. Passive studying is reading notes or a textbook, highlighting notes, or watching videos. Active studying is working on practice problems without a key or example in front of you, rewriting concepts or definitions without notes then checking them, teaching someone else (it can be a person/plant/stuffed animal/imaginary audience/pet/whatever) the concept and fielding their questions, drawing diagrams to explain topics, or even researching examples of a topic and trying to come up with a reason for why it is the way it is.
Researched along with the study cycle is a method for learning that works wonders. Preview, class, review, study. If your instructor has the topics for the next day in class, notes, homework, or something like that available, take time before class to look over it. Make a mental or physical note of what you do or don't already understand. Write down questions you have, and in class try to answer them. Familiarize yourself with vocab terms and key concepts. In class, actively take notes. Don't write down what is said word for word, put it into your own words. I obviously have some unconventional ways of thinking about things, use the comparisons your brain makes and understands. If you have the chance to interact with other students in discussions during class, take initiative and teach others what you know well, and ask about the things you don't understand. Form study groups with other students so you can teach each other and have motivation and accountability to study. After class, before the end of the day, take 5 minutes to jot down key points from class without looking back at your notes. Also make note of the concepts you still need more work on so you can focus on those during your study sessions.
Study in short bits often, rather than taking a huge chunk of time right before a test. It just works better.
For any and all math within a science class, start by identifying the equation(s) needed. Identify the units of each part. Ensure units cancel to your desired answer's unit. If not, convert some stuff. Rearrange equations before you put the numbers in. Keep every number with its unit, and write every single unit. It feels tedious, but probably 2/3 of the math mistakes I see in my students' work is because they had the wrong unit, didn't keep a number with its unit, or something along those lines. It's tedious and boring, but solving an equation shouldn't have surprising and unexpected results.
Along the lines of math, always practice and do homework with the calculator you are allowed to use for the test. You don't want to show up to the exam and not know how to use your calculator. It sounds like common sense but I've had students ask me right before an exam how to use their calculator. That is something you shouldn't make yourself expend mental energy on.
If your mind tends to wander like mine does, try keeping a blank notebook/sketchbook/paper next to your actual notebook/note-taking device. I like to doodle and write down whatever my mind wanders to there so my notes stay neat and focused. Bonus if your brain connects the concepts you learned to the doodles you did. This also helps since I'll come up with tangential questions or ideas from the lecture, and if I write them down my brain doesn't have to split its focus between remembering the ideas/questions and learning the content.
Go to office hours if they're offered and you have the time! If you're struggling, your instructors are there to help. If you're doing well, you can get extra practice, additional resources, or talk to your instructor about the stuff you find interesting in the course. When I took introductory chemistry, I didn't have time to go to office hours, but talking to my professor after class about the questions I had and the things I thought were interesting from class led to him suggesting I tutor for the class, which you can tell is my absolute favorite thing to do!
I'll update this if I think of more, and I'll post some of my sketchbook pages from when I took introductory chemistry if I can find them. Hope these help!