Purchase renters insurance or find out if your homeowners or renters insurance will cover your stored items.
Label all boxes and make an inventory.
Make sure you have the right size unit for your needs and allow for space between walls and ceiling for ventilation.
Use wooden pallets to keep items off the floor.
Consider unattached shelving for organization.
Place items up front that you will need to access more frequently.
If possible store couches on end and stack chairs seat to seat.
Use a good wood polish on your furniture and use blankets, sheets, or moving pads to protect items.
Make sure appliances are clean and dry, store slightly open and use the inside of appliances to store light weight items.
Store paintings and mirrors on end, use bubble wrap or packing paper for all breakables and pack boxes tightly.
Grease, drain, and clean all outdoor equipment and oil metal tools
Check your unit frequently. If going out of town have someone named as the emergency contact and make sure someone you trust has a key and the code to the gate, ask that they check your unit frequently. Make sure your lease agreement reflects the names, addresses, and phone numbers of all such people.
Report any suspicious activity, malfunctioning equipment, signs of damage, or pests to the rental office.