Ask About Ownership
Simply hiring a photographer to take pictures for your business doesn't necessarily give you the rights to use the photos they take on your website, print materials, or business cards. Be sure to discuss ownership of the images up front, and get your agreement in writing. For example, you may need to negotiate a Digital Rights Fee - a contract that clearly outlines how you can use the photographs and whether or not you need to give the photographer credit each time you publish a photo they took.
Discuss Retouching Fees
Thanks to the magic of photo-editing programs like Photoshop, many photographers now offer value-added services to remove small blemishes, clean up backgrounds, and even edit in people into photographs. All this digital photo magic comes at a price, so be sure to explore exactly what photo editing will cost before you sign a contract.
Ask For A Portfolio
Professional photographers are expected to maintain an active portfolio of their work so they can show of their skills to prospective clients. Review recent work of photographers you're considering using, and as with all contractors, take the time to ask for references.