I find that notes help me more than flashcards. Taking notes allows me to decide what is important in a lecture or passage, and writing concepts and ideas down helps me to remember them.
Out of the three methods I mentioned above, I have found that reading information helps me the most. I can process information better, when I have it right in front of me in textbook form. Being able to directly look at a history passage or a math concept in a book is the best way for me to absorb information. Which of the three types of learning methods I mentioned works best for you? Do you prefer another type of learning I did not mention? If so, what is it, and why does it work for you?
Here is a link which talks about different learning styles:
http://blc.uc.iupui.edu/academic-enrichment/study-skills/learning-styles/3-learning-styles