If you have, how is it going? How many times have you done it?
If you haven't yet, here's a little help.
Just open your notebook, grab your pen, and write the date. There. That's easy.
Now just let your mind come out of your pen. Stream of consciousness style. Or whatever style you want. You can say what you did the day before, or you can complain about something, or you can write something secret. Just blather on for three pages. Then you can stop if you want, and save the rest for tomorrow.
The thing I noticed is that my hand gets really tired. I am not used to writing long hand any more. It also looks terrible. I noticed my hand continually misshapes the letters...too many bumps and whatnot. But oh well...because no one is going to read it.