* Routine! Having a reliable routine means I am never lost for what I should be doing or where I should be. I don't organise because I am prone to perfectly planning everything -- I organise because I'm dysfunctional without it. For example: every Friday is laundry day. Anything that misses the Friday slot has to wait for next Friday.
* Don't stock your favourite foods. Everyone lives with temptations, but ADHD makes it that much harder to resist. I have a number of foods which I love and which I simply do not have in my home. No chocolate, no peanut butter, no bread, no pasta. I have these occasionally and as a treat. But if they are around they will get eaten. So I just don't keep them.
* Don't know your passwords. Use a program like keepass. If you know the passwords for sites and apps, you will log into them from more places.
* Go to an office to work, whatever "office" means to you. Make the hours regular. Try to create a distinct physical separation. The difference makes it easier to enforce rules about what you can do when.
* You see a topic on reddit, hackernews etc that you deeply care about. Don't open it. Don't read the comments. You'll struggle to stay out and -- as you can see from my comments elsewhere under this post -- struggle to control your emotions. Just stay away. That's what I should've done with this one.
* Don't take breaks if you're making forward progress. People say to take breaks, but in my experience it pretty much ensures you will derail the rest of your time. Right now, for example, I'm in about the 4th hour of a 5 minute break.
* Do your best on sleep hygiene. Being tired weakens your ability to resist impulse still further. You will say and do more things you'll wish you hadn't.
* Get a filing cabinet. Add folders. Get stuff off your desk as fast as you can. Empty your email inbox as completely as you can.
* Subject to your finances, pay your bills ASAP. You will forget them. Or worse: forget them, remember them, feel stressed about forgetting them, then forget them, over and over until they're paid.
Between ADHD, anxiety and depression, just being alive is exhausting. But I have gotten better at playing through the basic levels over time.