I'm pretty disorganized by nature, so I need something to help me stay on track. The simple act of reading through that todo list first thing in the morning helps a lot. "Oh yeah, I finished that, that needs a bit more work, that's half way done". Depending on what it is I'm working on, it can be as simple as 5 bullet points, or it can be headings and paragraphs.

I try not to be strict about the format, and it's certainly evolved over the years.

For instance, we have a weekly department meeting. There's now a section "Dept Meeting" in today's file with a few points I want to bring up. Maybe they'll get resolved by then, or maybe I'll add more points. The simple act of copying that file each day and removing what's no longer relevant means I have refreshed my memory, don't have to worry about stuff that's no longer relevant, and have a track record of what I thought was relevant.