During class - 3). In class questions

Use practice problems or exercises to help you understand and memorize the concept better

Understand why the wrong answers are wrong and why the right answers are right

Before going to class, get a hold of some old papers or practice problems 

You're going to get most of these questions wrong and it's OK. That's actually a good thing because you benefit from the Hypercorrection effect: "When you thought you knew the an...

If you're reading a book, watching a video, after every section stop and try to recite in your own words what you just learned. 

Tip: Note the topics you find more difficult to remember 

Great for revising and for spaced repetition

Write a question on the front and the answer on the back

Tip: use digital flashcards like the apps Anki or REMnote

Grab a blank piece of paper, pick a topic and proceed to brain dump everything you know about that topic

You have to link the idea to something that's already on the page

This is the best time to revise the questions you have written during class

It doesn't need to take too much time because you are not peeking at your notes, you're trying to recall straight from your memory.

Useful for recalling images, graphs etc.

Anki or REMnote comes in help because they let you drag a box over the pictures, answer it and then reveal the box. 

You can use it also for graphs, series of words etc.

Useful for processes and problem-based classes like math

Use mnemonics to help you with your enumeration. Use acronyms, associations, stories etc.