Many items can be eliminated when you move, but you do have to decide what you want to move. You can start by having three bins: one for donations, one for items to sell, and one for tossed items. The next phase would include what you will definitely need and what can be stored. If you have to downsize, some of the following tips should help with the process.  

Make a List

You should start the process by preparing a list of the items cannot dispose of at any time. For example, list your valuables, your family heirlooms, and your day-to-day essentials. By referring to this list when you are sorting your items, you can let go of excess. This inventory is something to keep in a safe or a safety deposit box and use for insurance purposes as well. 

Begin Sorting Early

Make use of the donate and toss bins beginning at least three months before the anticipated moving date. Take time to search through the paper-trail of information you have saved in the junk/file cabinet. Items seem to hit the file cabinet and never leave again. Pay attention to how many photos you want to take with you. Can you scan them onto your computer? Reserve a few minutes each day to focus on this task because it will be much easier in short spurts instead of waiting for the week of the move. If you tackle the job room by room, category by category (clothes, toys, etc.) it won't seem so daunting.

Furniture

If you know how much space you are moving into, downsize accordingly. If you have a large sofa, maybe you should donate it and purchase a smaller one. Your rooms throughout the house may be smaller, so use the same logic in the rest of the house. Don't move items that you cannot or will not use. When thinking of storing them, only do so if it makes sense that you are going to use them in the next year or two.

Storage

As the time of the move gets closer, you should have already decided what needs to be stored. Have all the packing materials needed in advance. Be sure to pack all the glassware individually and mark the boxes as fragile to prevent damage. Mark the boxes that will be in the storage unit clearly. Seasonal items can be placed in the unit and taken out as needed. Be sure to pack them so they are easily accessible.

With a bit of common sense and planning; your move should go off without a hitch. Keep what you need and all the sentimental items, but dispose of the extra clutter. You can enjoy your new space much more with a clean slate.