The first thing you need to do is assess your living space. Are you in a larger or smaller dwelling? Are there rooms obviously designated for specific purposes (kitchen, master suite, garage, linen closet vs coat closet, family space, dining room)? What rooms have a variety of optional purposes (office/guest room/storage space/laundry room)? What rooms do you and your family need (bedrooms, guest room, home office, kids space, workshop)?
List out what you want this house to have and walk through the footprint of the house and label the first designator that pops into your head. If you start contemplating this room or that room you will put yourself into a painful and never ending conundrum, so go with your gut.
What does this have to do with unpacking? Well, unless you packed each box and know exactly what the contents are, or if your movers perfectly labeled and inventoried every item, you are going to have to sort and place things where they belong. As you go through each box, you will now have designated homes. So instead of opening an overly taped package, looking at the contents and having no idea where to put things, and closing the box to deal with later, you can now put the box or the contents in the correct room.
Of course, depending on the change in square footage, some things may not have a new home yet, and that is totally ok.