There are a wide variety of shelf options available. Determine the amount you feel comfortable spending and consider what will suit your needs best.
Build Your Own - Probably the cheapest option, offers the most flexibility
Inexpensive metal or plastic shelving- A cheap and easy way to get started, although shelves may not last as long as other options
Deluxe Can Rotation System - These are the priciest way to go but are VERY convenient when you are really rotating and using your food storage items. Different versions are available to fit whatever size of cans you want to store.
Start with one set of shelves and add more as your food storage grows.
Plastic may be better than metal for storing heavier items (metal tends to bow in the middle).
Adjustable shelf heights will be useful as you store different types and sizes of foods and cans.
Baby Step #1 from http://foodstoragemadeeasy.net/