Start with a question, not a highlighter
Close your textbook and ask yourself what you can explain without looking. Write a short answer, draw a diagram, or describe the idea aloud. The goal is not to get everything right immediately; it is to discover what needs another pass.
Check, correct, and explain
Compare your answer with a reliable source. Mark what you missed and explain the correction in your own words. If you only memorize the answer without understanding it, a differently worded question may still be difficult.
Space out your practice
Return to important concepts over several days rather than keeping them in one long session. A simple plan is to revisit material the next day, later in the week, and again after a longer gap. Adjust your intervals to how well you remember.
Make flashcards work harder
Keep each card focused on one idea. Mix definitions with application questions and examples. If a card is consistently easy, review it less often; if it is consistently difficult, revisit the underlying concept rather than only repeating the card.