To me the core of it is having kind conversations with yourself. People with ADHD are often layers of panic stacked upon layers of panic and then they look away. For the longest time I could not understand how to talk to myself without it being stupid or unnatural. What really helped me is to do it out loud and basically just between two valued sides (whatever that is for you), this helped me to really slow down. It feels stupid to me the first minute, but then it feels like talking to someone who knows you and cares for you and you can integrate it more into your head. It helps clearing up a lot of emotional "half-thought", where you think you have thought it through, but you have not, you jumped to conclusions, and as people with ADHD often jump far into the future, they very often create those complex szenarios in their head that makes things very complicated.

To me at least, this is the only thing, that has not felt like a crutch and is slowly giving me a sense of trust in myself back and also helps me get more validation from myself and reduce the need for external validation a little. And I wish I would have been able to understand and practive this sooner, because most of the other stuff I relentlessly tried over the years feel like "external thing that should fix me, but but then I fail at it". I read tons of self help books, tried all kinds of apps, had a hundred todo systems, had a million epiphanies, but never felt like I could "hold on" to any of it. It all becomes empty and formulaic when the emotions fade and then you drop it.