Not studying at all is a complete gamble. It’s a choice for sure, but not always a smart one. Usually when I don’t study I believe that I have seen enough material to be able to take a test without reminders but it never quite works out as planned. It’s always safer to just do something quick rather than skipping studying entirely 

Colorcoded notes is a very simple and common way people study. Going over things you highlighted within categories you may have made. It is a good and helpful way for things you’re stuck on but this is another that wouldn’t be a first pick

Studying before bed is a good method, it makes your brain stay awake and digest information but the only downside would be forgetting what you studied the night before since it was right before bed. Definitely a very simple method, it might not be a first pick, but is definitely one of the second options.

Repitition is what it sounds like, simply repeating things from notes or study guides actually helps a lot more than one might think. It helps your brain remember a connection between the things and isn’t really time consuming

Memorization is not always some people’s go-to study method. Certain people need to write stuff down to understand it so memorization may not be on the top of the list. Memorization is a good way to study if you’re in a rush or just need to study for a few minutes

Spaced practice is when you take breaks between studying. I think this is a really good way of studying and letting your brain get a break while also making sure you remember what you studied after a period of time. It’s a very helpful memory trainer and is a great way to study.