Rabbi Moshe Chaim Luzzatto (18th century Italy) writes in the introduction to his clasic work of Jewish ethics, "Path of the Just:"
"I did not write this book to teach people information they had not known previously. My intention was to remind them of knowledge they already possessed. As a matter of fact, you will find that most people already know the information that I have written. But to the degree that this knowledge is well-known and its truth self-evident, is the degree that people forget about these matters and are not consciously aware of them in their daily lives. Therefore, the benefit of reading such a book does not come from reading it just one time. You might find only a few bits of new information. You will derive benefit, however, from constant review. Keep reviewing ideas for self-improvement - even though on a certain level you already know them. When you constantly review important ideas, they will be at the forefront of your consciousness and you will thereby be able to apply them."
Today, think of some ideas, concepts, knowledge, or wisdom that you already know - but feel that you would gain from having at the forefront of your consciousness. Devise a plan to review that idea as frequently as you can.
(see Rabbi Moshe Chaim Luzzatto - Path of the Just, Intro)