If you have put your home on the market, take a look through your home as if you were the buyer. Have you decluttered as much as you can, or are there some areas that still need attention? Don't forget the closets and other storage areas -- you want the buyer's to see how much room you really have, not how much stuff you have!
Sometimes having a lot of possessions worries a buyer because they wonder what you will do with all your things and if you will be able to move out on time. You should sort by using three categories: 1.) Things you will never use again. Then get rid of them; 2.) Things you might use again. Keep in mind that you will be storing these items for an unspecified amount of time; 3.) and things you use.
Minimize your shopping. If you usually take advantage of the canned goods sale and stock up the pantry by bringing in a year's worth of peanut butter or spaghetti sauce, you will need to retrain yourself to buy a month's supply at a time. It is amazing how much the contents of your pantry can weigh, and if you don't have the cost of a mover that charges by the number of pounds moved you will likely be saving yourself the trouble of moving unnecessary heavy items.