[domk]

I use org-mode in Emacs to keep daily notes, with the majority in one big file with an entry per day. The content is quite diverse - a mix of TODOs for the day (especially when I need to get through multiple smaller things that day), things to do or think about later, small notes to self about the code I'm working on, and sometimes quite extensive notes when thinking through the design/architecture of something new.

The last technique especially helps me a lot. When thinking through a hard problem, type out your thoughts in a semi-structured way, never deleting anything. Makes it easier to deal with problems that can be too large to hold in your head at once, to think about the aspects of something step by step, or to retrace your thought process and see why you made certain decisions earlier and maybe explore a different route when you get stuck. When finished, it can be used as a foundation for a design doc I share with the rest of the team.