I have ADHD, and am medicated, but it doesn't solve everything. I find starting a task helps, as then I often get into it and keep going, and the starting is half the battle.
Also, telling someone else what I have to do. I tell my dad if I need to do something on a particular day, like call the insurance company, and ask him to message me hourly and ask me if I have started it. The accountability helps. And fear and external deadlines do work sometimes, but they cause huge amounts of stress, so need saving for really important stuff.
I have as many routines and structures set up as possible, so I don't have to think about what I have to do. So meal plans, shopping lists, task lists. And a weekly and monthly schedule for me and the kids on the fridge door. I spent an entire weekend sorting them all, which was tough, but now I have to use much less brain power. I also have lots of frozen pre prepared ingredients. So frozen mince, frozen chopped vegetables, frozen jacket potatoes. It means I will make a healthy dinner and not get takeaway, as I don't have to defrost anything or chop vegetables, which would mean I wouldn't bother.
Everything that can be automated is. Alexa tells me when to take out the bins, and turns the lights on and off, and I have saved in my phone what bin goes out on what week. I have alarms set for everything. Even when DS has to get in the shower in the morning and when the kids need to leave for the bus. And lists and reminders and routines on my phone. All bills go by direct debit, and I have an account for bills only that a set amount goes in to so nothing bounces when I inevitably overspend.
When I have to do boring jobs like put away washing, iron school uniforms or wash up, I listen to an audiobook or podcast. It stops me getting bored and going on my phone halfway through, and means I am more likely to stick with it.
Cutting myself some slack and accepting this is how I am has helped the most. I have made myself get a shower tonight, because I know if I intend to tomorrow I just won't do it. I used to lie to myself that I would just somehow manage it, and then be really stressed when I inevitably didn't follow through.
I give myself twice as long as I think anything will take, plan to do half the things I think I can do in any day, and make sure I give myself plenty of downtime to recover.
I have a pile of toys to go to the charity shop that have been there over a year, and can't get into the back room because it's that piled high with junk, so it's far from perfect. But I accept I am like this now, and it's a brain difference and not a personality defect, and so myself esteem has improved, which means I am more able to be practical and come up with solutions rather than hate myself for not being able to do what everyone else can.