Use pallets to keep goods off the floor and help keep them ventilated if storing in non-climate controlled storage. Such as for your mattresses
If possible use uniform boxes and fill to capacity, use towels, newspaper, or bags to fill in empty spots. This prevents boxes from collapsing. Boxes wrapped tightly with tape will prevent dust from entering. Label on all side for easy identification. Clearly label fragile items and make sure they are packed on top.
Books, Documents, and Heavy Tools: Pack books flat to protect the spines; use small boxes to avoid cartons that are too heavy to move. Put heavy items on bottom.
Dishes and Glassware: Glass items should be individually wrapped, "nest" cups and bowls, stand plates and platters; fill air pockets with wrapping paper or foam peanuts. place a layer of paper in bottom and in top of box.
Lamps: Remove shades form lamps and pack seperatly.
Mirrors and Glass: wrap well with paper and store on edge, not flat.
Tables and Furniture: Remove legs from tables to save space. Wrap legs to protect. Cover furniture with blankets or plastic wrap to prevent scratching.
Beds: Store mattress on end to save space. Leave slip cover on mattress or cover with plastic to keep clean. Wipe metal railing down with oily cloth to prevent rusting and wrap in paper or cloth to keep from staining.
Use valuable space inside dressers drawers and large appliance, such as stoves and refrigerators, to store small items such as towels, linens and small fragile items. Secure items in drawer by filling empty spaces with towels, clothing, or paper.
Appliances and electronics: Clean appliances thoroughly. Refrigerators and freezers must be defrosted and dry. Washing machines must be completely drained. Place some kind of odor absorber inside: baking soda, charcoal, coffee. Should be stored with door open slightly to prevent BO and/or molding
Motorized Items:Drain and winterize any motorized items; lawn mower, blower, motorcycles, etc.
Metal items: wipe down with oily cloth to prevent rusting and cover or store separately to prevent staining
DO NOT STORE: Hazardous or toxic materials. All flammable liquids or gasses should be in proper containers and have a vent. DO NOT store food or food items to prevent bug/mice infestation.
Store your largest items first. Items that you'll need most often store at the front of the unit.
Leave small walkways between the boxes and furniture so you can easily get to the items you may need to access without moving stuff around.
Be certain that everything is stored dry, as any moisture may cause mildew. Moisture is bad for virtually all property or goods.