These may have already been mentioned:
Subfloor soundproofing for double storey
Manhole in garage for double storey especially as we have converted our garage into home office and can do extra wiring…

One I found at kitchen signing off, if you have higher ceiling - I have 2550mm then make your overhead cupboards taller so you don't end up with a…

If you are going to use your garage for more than just parking your car in it, then I'd suggest you get two lots of lights in there.
One for overhead…

If you're getting a water point in the fridge cavity, make sure the water point isn't going to impede on your fridge depth. Sometimes it's better to relocate the tap…