Calendar with several reminders (3 days before, 2 days before, several hours before etc.) for long term events, alarms for everything up to a week away.

Visual and spatial cues where I need them for routine building. I have dedicated spots (imagine a shelf) for important stuff, let's say medication. It only works if the routine is built around it, otherwise the spot becomes "invisible" after time and completely phases out of existence for me. Again, routine building is key.

To support that, or to be reminded of temporary chores around the house etc., I sometimes program restaurant pagers that buzz and blink, they're integrated into my home automation setup. Here, the key is to predict times when I'll have free time to execute the task and be in the right mental state to do it - again, took years to figure those times out. Change something in my environment or time schedule, and I'm fucked.

Well organized notes, I use Joplin. The key here is a multi step process, e. g. to go back to the thought dumps and organize them later, when there is time.

Overall, I want to add that improvement is definitely possible - I have kids and run a business, but if all those weird methods and quirks sound esoteric and exhausting to regular folks, rest assured they are.

I've found that an A6 size notebook was easier to always have with me because it fit in my pocket the way a smartphone does. But I've been using an A5 since I stopped going to an office and, well, I had some A5 notebooks lying around.

I've also found that the best thing I learned to do with the notebook was to have very few things (the most important things) written down in the front and "other" things written in the back. Focusing on the things in the front until complete (or has become less important relative to some other thing) and marking them off is tremendously helpful. Folding the corner or bookmarking the most recently written on pages allows for easy navigation.

It's a bit like a stack and a heap. When a new "other" thing has my attention, I write it to the heap in the back of the notebook. The most important things (3 at most) are written to the stack in the front of the notebook and popped off (struck through) when finished or moved to the heap (writen in the back of the book because it's no long a top priority). Eventually the back and the front meet (a stack overflow) because you're not erasing anything and you need to use a new notebook.

I couldn't tell you why this is so helpful other than to say that it frees my mind to write down whatever has my attention and is important enough to remember but not important enough to prioritize now.

Other than that, I use a calendar app and Google notes for things I want in digital, synchronized form.

Also, regular exercise seems to help me stay organized. But that's probably not what you're asking about.

Routine, routine, routine. When my routines get messes up, all hell breaks loose.

I have a (or multiple) paper notes on my table to my left, where I write down stuff. I often separate them into columns or paper notes of "today", "todo", etc.

At work, I have a text file with sections and bullet points (one-liners) for Critical today, Maybe/Opportunity today, and todos/backlog. That serves as a personal list and for "to check" or "small things to do" notes in addition to our task ticket system (with planning, descriptions, and assigning, etc; for Software Development).

More broadly, I'm okay with noting stuff down, and not really using it that much. It varies quite a lot whether I am able to tackle them or not (procrastinate/evade). But that's okay.

I also don't get a feeling of accomplishment when check-marking or striking through done items, which some other people seem to get. So it's more of a write stuff down for more structure and offloading from my mind, and to get a better overview.