Write one every night of stuff you want to get done in the morning. Ryan Holiday suggests an index card and a sharpie - then you aren't tempted to write too much.
Start the morning by looking at the index card. Take it with you if you have to, but check off the boxes as you go.
End of the day, look at your index card. If the task was important, put it on the new index card. If it's not, forget it. Move on. Don't let it drag you down.
But keep the index cards.
Look at them every month and recognize that you did all that.