I make a new note each day titled the current date (17 August 2020.)
You can either make a digital note or use a physical notebook's page on your commonplace notebook.
Write anything. This note is (and should be) messy. Do a 5-minute mindless-writing (freewriting) practice each day in the morning. Add your to-do list to it. Or what ideas you are thinking about. The main purpose is to have a "that" place so that your unfinished ideas won't die in your brain.
If you learn anything major, make a separate note and explain as you would explain to a 5-year-old. This helps you articulate what you have understood and check any holes in your understanding. And link that to your daily note, under a heading, what I learned.
As you write those notes, you are also documenting your learning. As we forget most of what we learn after some week. After 2 weeks, you will have a library of thoughts and separate notes that explains what you have learned during the day.
FAQ
Why have a note-taking app?
Invest in a note-taking app essay will help you.
Which app do I use?
I use Evernote, but in this article, I have argued that why it doesn't matter which program you use.
Photo by Kelly Sikkema.