I wish the article had a bit more meat to it. Not that this is a sin but he's just parroting things said in about 1000 other places by 1000 other people. Pen and paper good. Check. Daily journal. Check.
The second image of the journal page seems to show a list of possible approaches to a problem. The fourth image looks as if it has performance data and evaluation of a working system, so that is a couple of ideas. I think it is quite a brave thing to post the actual images. Perhaps fortunate the OP does not record team dynamics in his journal.
I work as a teacher, and I use a cheap page a day diary to record a few key points from each lesson. The 'readymade' aspect of the page a day diary seems to reduce the 'threshold' for making notes.
* Write a todo. Ex: Log errors from Fb. * Ask a question if I'm stuck. Ex: Will Log4R block the reactor? * Play with various approaches. Ex: Write in thread, plug into Goliath's logger. * Note any bugs. Ex: Logger blah blah * Rinse and repeat.
I know its a silly example, but you get the idea. Hope that helps.