I would absolutely recommend creating handmade flashcards of key terms that the teacher mentioned to "look out" for on exams, but for a digital option, using Quizlet to create flashcards for key terms would be great! I would also recommend setting up a Word document or Google Document with a two column table (one column being a possible exam question, and the next column being an answer). Covering the answer column while attempting to answer your pre-made exam question is great to test exam material from memory (making studying very efficient!).