When we moved, the removals company did the packing. They offered three service levels, we took the basic one. It worked like this: we did (almost) nothing!
Obviously you should pack essentials to cover the period between properties and keep them with you as if going on holiday - clothes & kids' stuff. Also, mark a few things that you will need to find immediately in the new property (kettle, tea bags, mugs, foods, cleaning equipment, telephone, whatever).
The company simply packed everything, and label it all methodically. Drawer contents were kept in the drawers, clothes from wardrobes were put into tall boxes with a hanging rail, and so on.
If you have special items such as expensive wines, a piano, unusually fragile things, you do need to let them know. If they are reputable & experienced they will have seen it all before and know how to pack appropriately.
Once in the new property, make sure you get them to put all the furniture and boxes in the correct rooms.
They will re-build furniture but with the basic service they do not unpack the boxes again. the next level up gives you that. (The top level does everything including setting up computers, internet, plants, plugging lamps in, glasses back into shelves, etc etc etc. Bonkers expensive and they hate doing it!).
The real tip is to use the move to get rid of as much accumulated, unwanted stuff as possible!
Hope this helps.