I have ADD and still struggle with it well into my adulthood. I've learned a few things over time:
-as a previous poster said, reframing and knowing how to reframe is important.
-sometimes, you have to say something out loud to really understand it or to help yourself better act on it.
-transitional activities are AMAZING. Washing your hands, standing up and changing position, and I'm sure there are many more out there that can help you move from task to task easier. Do something you feel like you can do first, and the bigger tasks won't seem so bad.
-you don't have to be the best one at everything you do. you deserve to feel good with yourself just for showing up. no seriously. even if you're not enough for other people, you're not looking to fill their cup...your life is about filling yours.
-I complete tasks based on if-then statements. If I'm in the kitchen, I'll wipe down a surface or put a dish or two where it needs to go. If I'm in the bathroom I'm wiping down a surface there, too. Tasks by location seem to work for me best, because everything I'm doing/planning to do is within my sight. Small cleaning tasks help me let out some nervous energy.
-A collection of fidgets are your friend(s)! A good fidget and some background music and I can finally focus on a mental task lol
-Not every ADD/ADHD behavior is going to apply to you. You are a unique human being, and will not fit into every box so neatly. In fact, consider yourself a complex person who "exhibits add/adhd/neuroatypical behaviors" not a human embodiment of your neurodivergence.
-With that previous framing, also realize that perspective on yourself doesn't invalidate your inclusion from these groups but instead lets you understand you can be a part of many, many groups in your life, and that's good! You're not an outsider to the world, you are a part of it!
-Whatever weird way you have to go about something to get a task finished or to begin a task is valid as long as it's harmless. People are going to give you shit for it but honestly? they suck lmao. If you gotta put on shoes indoors to make sure you cook yourself a meal, or whatever, go for it. People who aren't neurotypical can change their trajectory or mindset with tactile, auditory, and other stimuli. It seems we react to these things with a certain sensitivity that others don't have.
-Medication can be helpful, but sometimes you need to ask yourself if it's still helpful once in a while. Only get off meds with the guidance of a professional or you will experience heavy withdrawal symptoms. Maybe your 24 year old self needed meds, and your 25 year old self didn't, and your 28 year old self needed them again. All of this is okay. There's nothing chemically wrong with us, but our environment and lifestyles can make it extremely hard to successfully achieve our goals and overall function, so when those things around us change, we need to step back and discuss with an expert about if we need to change how we respond to these new settings and schedules. Therapists that help give you the mental tools to handle existence (that understand add/adhd/etc) can help you figure this stuff out, always seek an expert in the field and don't be afraid of second, even third, opinions.
-Keep a tab on new information and studies about the behaviors affecting you! You never know what sort of breakthroughs that might pop up that resonate with you!
Sorry for the long ramble, but I hope I can be of some help to someone! :) Feel free to add me if you want, just keep in mind that I'm 29 lol