Have plenty of bags for life, plastic bags, bin bags, honestly any kind of bag you can get your hands on, somewhere handy.
I am good at packing boxes but every time I move, without fail, there are lots of random items that either don't belong to any box, or have been left until the end (essentials) but we didn't factor in a box, or any such situations.
Then you start stressing and rushing around trying to fit them in somewhere. Instead of making up another box, just throw stuff in the bag for life, put it in the car and deal with it when you unpack. Maybe this isn't that efficient if you're storing everything, but it might come in handy somehow. Bags for life have saved all my moving out days.
Label/mark absolutely everything.
Have two, or three, of everything (tape, marker, labels, etc). In the chaos of moving day, they will fall behind a radiator or inside a box and you don't want to waste time looking for them. Just pull another marker out of your bag and continue the job.
Don't throw away cupboard food you don't think you need to take with you. If it's non-perishables, spices, sachets, move them over. When you settle in your new kitchen, you'll have your backup cupboard stuff there, just in case.
Bedding, towels, basic nightwear and toiletries and phone chargers handy. List or diagram of where everything is. You might think you remember in which order you stored the boxes, or what's inside each suitcase, but you won't. Photos, if it's easier, and write on them and save to favourites. Good luck!