Okay - seasoned forces mover here.
If they are completely packing for you, they'll literally pack everything - even cereal in bowls if you leave it!!! Don't recommend that though 
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Take down all of your pictures and put in one place.
Pack a bag of stuff you don't want them to pack - like knicker drawer stuff, photo albums, passports etc.
Pack anything they won't take - like aerosols/plants etc to take with you in car.
Take apart your beds asap and sleep on the matresses with sheets.
Put all bed screws/allan keys etc in a plastic box or similar to keep safe for when you arrive and need to put beds up.
Empty any medicine cabinets.
Use up empty spaces good for storage of moving goods.
Put current laundry into black bags and then in laundry bin.
Use waste paper basket for storing stuff.
Use shoe boxes to put stuff from kitchen junk drawers in - chuck out stuff you don't need.
Any cleaning products you need afterwardas to clean your house, keep out or put in a bucket altogether.
Take down any curtains that you don't need to use before the move - like spare room dining room etc
Keep a list with you of people you need to contact for address changes/emergency numbers.
*If you're packing yourself, get off your bum and get cracking 
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Good luck!!!