My list - some repeating already mentioned, many things that most people do already but mentioning for those who don't;
I used to stand waiting for the kettle to boil, but it's amazing how much you can do in those couple of minutes (wiping work surfaces/putting stuff away off the draining board etc)
If there is someone else who can help you, two people emptying the dishwasher is more than twice as quick as doing it yourself.
Meal planning: makes shopping & food prep so much more efficient and less waste. You can still be flexible if you see something on offer in the supermarket
I write my supermarket list with a column for each area in the supermarket (Fruit & veg; grocery; chilled; frozen; drinks etc) - throwback to lockdown's one way system when it was a nightmare if you had missed something. I've kept on with that as shop at a very large supermarket & much more efficient.
If we have people round for dinner, I keep track of what we served them a) so I don't repeat the same thing for the same guests and b) so I can repeat successful dishes for other guests.
Keep thinking I should do the same with family meals.
Definitely agree with shopping for multiple birthday cards at once, even a few months ahead.
I have a 'master planning list' for holiday packing, so I don't have to think about it from scratch each time, just adapt it for that particular holiday. I update it after a holiday if there's something I realised I hadn't packed that would have been useful.
I also have a master planning list for Christmas, ie checklist for things like cards, wrapping paper, candles etc etc, again so don't have to think from scratch each time.
As you can see, I'm a bit of a list maker! Pre smart phone, I used to keep master lists on the computer. Now on my phone. That said I love an old fashioned paper list so have a nice notebook which has my to do list at the front, and I start at the back for other lists (I have a page for TV/film to watch - ideas I've picked up off friends/ MN/magazines etc; ditto books to read; recipes to try.