Place labels on the outside of each box to identify its content.
Use uniform size boxes for easy stacking.
Use masking tape to seal boxes.

Tape up the bottom of all boxes for reinforcement

Clean and anything to be stored to prevent attracting vermin.
Stack lighter boxes or boxes with breakables on top of heavy or bigger boxes.
Remove all batteries

Use quality boxes. Supermarket boxes may seem like a saving, but they don’t stack well and often collapse. Always fill a box. Never overfill, as they bulge and will be difficult to stack. Under filled boxes should be stuffed with newspaper so they don’t collapse when stacked.

Plastic tubs make excellent containers for bulk storage.  A cedar closet is an excellent storage solution for a basement or garage.

For keepsakes or valuables use Archival board boxes.

Storage boxes made of high density polypropylene like Rubbermaid or Sterilite are safe for storage, these containers are used by conservators.
Acid free tissues paper for storage of keepsakes, family heirlooms and collectibles.

Appliances -

A refrigerator or freezer should be thoroughly dry and stored with its door(s) slightly ajar. A deodorizer placed inside fridges or freezers is also a good idea to maintain freshness.  Don't place items inside the shelves and linings can be easily marked and damaged.
Washing machines should be cleaned and fully drained, make sure the door is kept open to allow adequate ventilation, use the travel bolts if you still have them. Mark hoses “hot” or “cold” if not indicated.

Furniture -

Spray all wood furniture with good polish before storing.
Sofas and mattresses should be stood on end on a plastic sheet.  Mattresses need to prop them up so they stand straight. Otherwise, they may get bent out of shape and become lumpy. Cushions should be wrapped in plastic.
Tables should be disassembled and their legs wrapped in paper. Tables that cannot be disassembled are placed top down on plastic sheet with the legs pointing up.
Keep upholstery off the floor and a light dust cover should be placed over your furniture. 
Lightweight chairs should be stacked "seat to seat".
Pictures, Paintings and mirrors should be wrapped with bubble-wrap marked FRAGILE and stacked on end. (not lying flat). Do not sit glass directly on a floor. There must be some wrapping or other soft material between the glass and the floor.

 Electrical items -

Do not use newsprint to wrap lamp shades
Wrapping items individually in bubble-wrap, packing them in cartons, and sealing the top will offer protection for your electrical items.
Stereo arms should be secured
Cookers should be thoroughly cleaned before storing. Bag up any loose parts and stick them and the instructions to the appliance.

Computers and equipment
Computers need special care.  Bubble-wrap and good quality packing cartons will do the job. Use some packing or linen in the bottom and top of cartons.
Computers have "self parking heads." If you are unsure about your computer, refer to the manufacturer's manual, or consult your retailer, especially if storing for longer than six months. Pack out any empty gaps with packing materials.

Books and Documents -
Temperatures between 60 and 75 degrees and humidity levels between 50 and 60 percent are ideal.
Do not place your boxes of books or documents directly on the concrete floor. 
Keep important documents in one box, clearly marked
Books should be packed flat to protect their spines. alternate the spine position to keep the stack level.
Use packing to fill out empty pockets in the boxes. 
Do not overload the box
Pack records or similar on their edges to prevent warping.

Photos/Photo Albums/Scrapbooks - Always use care when handling negatives to avoid fingerprints, scratches, dust and sunlight damage - Store them in a quality or acid-free material/box/carton to give them the maximum protection. Old photographs tend to curl over time. To keep them flat, place them between two pieces of cardboard and tape them together.
Board games- store your games vertically. Enclose the pieces in zipper-style baggies to avoid spilling. Place a sheet of acid-free paper or plain cardboard between them. Avoid direct sunlight so the colors on the cover don't fade. Place a sheet of used fabric softener inside the box to give older games a fresh.

You can visit Preservation at the Library of Congress to find out how to care and store Newspapers, Motion Picture Film, Manuscripts, maps etc...

Dishes and Glassware -
Place a layer of packing on the bottom and at the top of boxes containing glassware. 
Wrapping silver in NON ACID tissue paper or plastic bags can help reduce tarnishing.
Wipe chrome or cast iron with a little machine oil to help retard rust.
Stand plates, cups, bowls, saucers and platters/casseroles on edge. 
Fill all empty pockets with packing material/scrunched paper
Label boxes as "fragile"  For FREE Fragile boxing labels - Moving Labels
Silver – Should be stored in a box made of wood.  Pretreating each piece of silver with a tarnish-retardant polish when storing for long periods of time or warp each piece with acid-free tissues.  NEVER allow foods to stay on to silver for long periods. This can cause staining and corrosion. Remove from food items immediately and rinse well, until you are able to wash silver.
Cleaning CORROSION caused by food or salt can be removed by soaking silver in a mixture of hot vinegar and salt for up to 5-minutes at a time. Use two cups of vinegar for every tablespoon of salt. Rinse. Dry well. humidity levels low in your storage area Place few capsules or small dish of activated charcoal to the Silver storage area, to stop the gases causing tarnish to silver and/or a single piece of white chalk placed in the storage box prevents tarnish.

 

Bedding and Linens/Textiles-
Textiles:  To discourage mildew in closets and storage area for textiles, twice a year empty all items from closets and/or storage area and wash wire shelving with mixture of ¾ cup of chlorine bleach and 1 tbsp powdered laundry detergent in 1 gallon of warm water and let set for five minutes then rinse with clean water and wipe completely dry before replacing items. DO NOT use this mixture on WOOD shelving.
Cedar chest or cedar for storage aroma; cedar wood has acidic oils in the wood.  When placing items for storage in cedar chest always wrap the items in acid free tissue or triple-washed cotton muslin.
Bedding & Linens carefully folded and stored in dresser drawers, wardrobe-style cardboard cartons or cedar chests. Furniture with drawers can be utilized as storage places for knick knacks, china, silverware, and small items or excellent packing cases for blankets, towels, tablecloths. Wrapping silver in NON ACID tissue paper or plastic bags can help reduce tarnishing.
CAUTION: Textiles, such as samplers, painted and embroidered pictures, and beaded work should not be vacuumed.  Store textiles flat, if folding is necessary, avoid sharp folds by padding at the points of folds with strips of washed unbleached muslin or old sheets.
Quilts - Vacuum the quilt through a clean fine fiberglass screen which will prevent any part of the quilt from being drawn into the hose. Vacuum both sides.  using acid free tissue paper or rolls of washed unbleached muslin or old sheets place between the folds.
Sleeping Bags – Before storing hand wash in a bathtub with lukewarm water and mild soap or detergent and rinse.  Drain the bathtub and press water from sleeping bag DO NOT WRING SLEEPING BAG.  Remove from bathtub, place on towels flat to air dry or drape across indoor clothesline or outdoors clothesline on a sunny day. Store sleeping bag in large storage sack and stored laying flat under a bed - do not store rolled up. 
Curtains and posh frocks are better hung and wrapped in plastic. 
Soft plastic baggies are not recommended by their manufacturers for the storage of heirlooms and collectibles.
Antique textiles - storage area should be clean, cool, dry, dark, and as free as possible from drastic changes in temperature and humidity.  Colorfast and washable items should be washed and stored unironed, unstarched and unblued. (Information on wet cleaning cottons and linens, quilts and coverlets, and samplers is available upon written request from Smithsonian Institution at info@si.edu.)

General Clothing / Wedding Gown/Formals-
Clothing and personal goods should be packed in strong clean secure cartons. For jersey or knitwear dresses, opt for folding instead of hanging. Avoid using mothballs; they are not necessary for preserving clothing.  Clean storage area by vacuuming, dusting and airing-out.  If needed paint closets, closet shelves or drawers
Items to roll rather then folding are underwear, socks and ties.
When hanging garments for storage; allow enough space the garments can hang naturally and air can flow between each.
Remove all jewelry and check pockets before storing.
Knit garments should never be hung, fold and place tissue paper between fold.
When hanging a garment always use the support straps or loops that come attached to the garment.
Wire hangers – do not use unless covered with tissue paper.
Plastic hangers give minimal support for lightweight shirts and blouses.
Padded/suit hangers are for sheer fabric blouses, jackets, and tailored garments or suits.
Traditional hangers with horizontal bar are for folded slacks/pants
Clothing stored in plastic dry cleaning bags can get mildewed.
Wedding Gown/formal dresses – Make sure to have a proper hanger for the shoulder line.  Steer clear of wire hangers.  Place Acid-free tissue on the shoulders and around the neckline of the dress.  Gowns made of a synthetic or a cotton-synthetic blend (as are most modern gowns) - use buffered tissue paper, if the gown is has any “real” silk or wool use nonbuffered, use 3 to 4 packages of tissue depending upon the fullness   Formal wear needs breathing space, proper form and protective covering to stay in good condition. Cover with a breathable fabric or paper bag is best for long-term storage
Suits - dry clean, Place Acid-free tissue on the shoulders. Cover with a breathable fabric or paper bag is best for long-term storage
 

Tools and other miscellaneous items -
Retard rust; wipe all metal tools with a rag containing a few drops of WD-40 or motor oil.  Long-handled tools such as rakes, shovels, etc., should be cleaned, lightly oiled and tied in bundles.
Shovels, hoes, rakes and hoses can be stored together in empty trash cans.
Stack Trash cans inside each other
Tires - Mounted and laying on the side in garbage bags away from the elements. Just stack them one on top of the next. They do not like heat or cold so a basement is better than a garage. Just keep them away from the heater.
Paint - Upside down, on cardboard and in a cool place where it can't freeze, and where it won't hurt anything if a can leaks a little.  Full cans keep better.  Heat accelerates deterioration, so try not to store it in direct sunlight, a hot attic/garage, or next to something warm like a water heater or furnace.  
Bicycles - To retard rust, wipe all metal surfaces with a rag containing a few drops of WD-40 or motor oil.

Holiday Decorations
Ornaments and decorations should in their original packaging
Remove hooks and hangers, ornaments and decorations use tissue paper for wrapping and place in a cardboard box lined with tissue paper.  Select boxes that are fairly shallow but large enough so that two or three boxes hold all tree ornaments. 
Angel hair and tinsel can be stored between ornaments for added protection.
Tree lights also should be wiped clean. Wrap strings of lights around a piece of cardboard.
Washable decorations, such as tablecloths, should be laundered before storing
Store in Cardboard boxes, Keep boxes off the floor to keep moisture out.