Haven't read though them all yet but thought I would add the things that help me.
Shared email for bills/nursery etc, only use it for this so it doesn't get cluttered.
Share and sync calenders, DH finally learned to use it when events clashed and mine was in the calender and his wasn't! He had to sort childcare.
Spend an afternoon filling all important dates in the calendar, insurance renewal, contract end dates, birthdays etc. Set to repeat yearly and have alerts at a time that is suitable for you to do something about it. New things go in that very moment or I will forget.
Every 4th Thursday evening I have alert to order my prescription and look at the next 4 weeks. If car insurance is due I will run a couple of comparison sites, write cards/pick presents etc. If I can see a very busy week coming up I will plan some easy meals/batch cooking etc so it is stress free. Even when I have a lot to do it never takes more than an hour and I know I am ready for everything!
While generally my rule is declutter as much as you can in some cases it works to have extras. We have bags for swimming, gymnastics, yoga etc. Each has own Hairbrush, ties, towels, water bottles etc as needed. When home bag is sorted straight away and repacked, when kit is washed it goes straight into bag. Basically as soon as you get it get everything ready for the next day!
It helps to look round your house and see the problem areas, also think about stressful points of the week. What can you do to make them easier? It can take time to build routines and find what works for you but I am getting their slowly.
For me I have to prioritise ease of use over aesthetics. I may want things to look Insta worthy but if it doesn't work for me it will only look nice for 1 minute a month!