I periodically print a to-do list on a quarter-panel of an 8 1/2" x 11" paper sheet. I fold it twice (by length and width) and carry it in my back pocket. I may add to-do items to it with a pen or pencil. I cross off finished items.
When most items are completed I create a new updated list and toss the old one into a "pile" (my favorite data structure!).
When most items are completed I create a new updated list and toss the old one into a "pile" (my favorite data structure!).