I'll mostly just copy/paste since I posted this elsewhere a few days ago.

Short answer: https://rtalbert.org/gtd/ (I'm not that guy. That's just my favorite resource on the topic.)

Long answer: This is the organizational system I use for tasks at work and in daily life. Once I know what I need to get done and have it out of my head, it frees me up to (1) be deliberate about how I spend my time and (2) focus relatively distraction-free on whatever I'm doing at a given time, even if that's something simple like watching a movie without wondering whether there's something I forgot to do for work.

The author's goal really resonated with me: be okay not doing what you're not doing. It's not always about doing more. It's about deciding what you need to do, doing that, and then not having to stress all the time. The article is tailored to academics, which was where I worked at the time, but I still use it now that I've moved on, and I see no reason it is not generally applicable.

I know you asked for something simple, and this seems like a lot at first, but you don't do it all at once. Even the author of the article recommends that you start small. I spent years doing just the first few steps (mainly Collect, Process, and Simple Trusted System) without even attempting bigger-picture planning and review stuff, and it was still life-changing for me.

If any of this resonates with anyone reading, I'd recommend you give the first step a shot today. Keep it simple, start small, but actually start.

ADHD-specific info: I've used this for about 5 years, and for 4 of them I was undiagnosed, unmedicated, and mostly didn't know what ADHD was. Even then, it was incredibly helpful for me, but it definitely wasn't a panacea. Combined with meds, it's been really great for me. If anyone is curious about specifics of how I do things, I'm happy to elaborate as needed.

Bonus for ADHDers -- it's a set of articles you can use to put off whatever you're supposed to be doing! I'm quite sure that when I started, it was because I was trying to avoid something important like grading :)

I've been using Anytype (like obsidian or notion) to track longer term things, things I need to remember, or references for hobbies (not everything).

And also a reminder app for medium to short term time-sensitive things so i don't forget.

I feel like it's been an improvement.

very few things stick more than a few months

months

Months... How do you make things stick for more than 2-3 days ? 😭😭😭

DBT

Laundry has always been a struggle for me. I'm guilty of the classic laundry chair.

I got one of those shelves that have the square shelf things and several cloth drawers for them. I don't really fold anything anymore. Socks in one cube, underwear in another, tank tops in their own, shorts in theirs, etc. I do hang my pants and long sleeve things. And I have a longer box thing for my tshirts to lay out semi flat in so they're not getting too wrinkled.

It's helped me a ton. Just throw everything in it's box and tada. I like sorting things, but just hate the folding part so this has been a saver.

Going for many super short walks during the day. Office workers are supposed take a 5 minute stretch every hour to stretch, so use that. This helps me declutter the brain.

Starting a task is hard, but so is stopping! Attacking "hard" tasks with momentum instead of willpower: I don't want to organize the freezer. I can tidy the floor in the storage room. Then empty the laundry basket. Now I have momentum and can attempt a breaching maneuver on the freezer: throw away some old food from the freezer. Usually this snowballs into sorting the freezer. If it doesn't, then hey at least I threw out some old food.

Loop Habit Tracker from F-Droid (Android only). It notifies me with a yes/no question about certain habits I'm trying to maintain. I set the notifications to come back immediately if swiped away without an answer. Keeps me accountable.

Bullet Journal — the original method described by Carrol, not the fancy spread-and-decoration bullshit. Write everything down as it occurs to you, indicate whether it's a note or a to-do with different bullet points, and at the end of the day decide which tasks to put in tomorrow's notes and which to discard. Date each page and list the page number in the index of it contains long-term notes (eg. quite from a contractor, birthday present ideas).

It's easy, it's fast, and it doesn't break if you forget to do it for a day or two or two hundred.

More controlled routines helped me a lot. I'm committed to stuff like taking a photo walk and doing a language lesson every day.

Also started using more to-do tracking apps, and also using paper almanac and notebooks and a Post-It wall. If I need to do something, I'm more likely to write down somewhere, and I'm actually getting stuff underway!

I print off a calendar for the year, creating a shorthand note on my current aims, I scribble in the shorthand on the calendar on what I want to do for the week and check it off as I go. Staying on top of my hydration and a healthy dose of “Doing less is doing more” has made me as productive as I can be with no prescription assistance. Best thing you can do is build a personalized toolkit with a legitimate adhd book.