When I was still a teenager I started a quote book. At the time I was a cross country and track runner and probably 90% of the quotes I gathered had to do with running. Today my focus is very different, but I still like to gather the wisdom of others and store it in a notebook. I have the same binder I had when I was 17 and I still add to its pages from time to time.
I write mine one after the other in no particular order and unsorted by topic. You could be more organized if you want.
Have your kids start their own quote books filled with phrases and quotations that mean something to them. You can kick it off with a quote finding project. Search online or in quote books for pithy sayings and inspiration.
Then once you have 20 or so gathered up write them down in your best hand. Whenever you come across something in a book that you want to remember or someone hands you a paper with a great thought write it in your book.
This is a great project to kick off a new year and resolutions to become a better you.