Use wooden pallets or boards underneath furniture and boxes. This will prevent condensation from damaging them.
Leave a small airspace between your stored items and the wall of the storage unit for ventilation.
Store items that will not be needed to the rear of the storage unit and items you will need access to toward the front of the unit.
Store heavy items on the bottom and lightweight items on top.
Store smaller, more valuable items to the rear of the storage unit and large items toward the front of the unit.
Cover everything with plastic sheeting. Wooden furniture should first be covered with blankets to avoid abrasion and moisture damage. Plastic sheeting will protect your stored goods from both dust and water damage.
Pack your storage unit as tightly as possible. Tighter packing helps to protect stored items from moisture and dust and reduces the space needed to store you property.
Use a high quality disc (round) padlock to secure your storage unit. This type of lock is difficult to cut or break and offers maximum protection for very little money.