If you regularly write your thoughts, a journal, etc., you know that after a while it takes a lot of space to store these notebooks.
Make the notebook’s “paper” from a material you can write on. When you finish the journal, you process it (by heating, chemically, etc.), and it will shrink considerably in size, while still leaving your writings legible.
By consciously thinking once a day about one important thing you have learned that day you’ll: fix it into your long term memory; motivate yourself to learn something new every day.
Keep a notebook and get into the habit – just before you go to bed – of thinking about what you have learned that day. Write it in your notebook. Keep the notebook beside your bed to have a visual cue to help you remember and turn this into a habit. After a year look back and see how you progressed.