This photographer also said he ran his first newspaper advertisement upside down and got more than a thousand calls telling him that he had wasted his money running that ad. The photographer gave each one of those callers a sales pitch and ended up selling about half of them on having him do their photography. A little innovation every now and then has never hurt any freelance photographer. In order to use a photograph of a person, someone's pet, or a recognizable building or piece of property for advertising purposes, you must have a signed model release. This is usually easy to obtain.
Some studios incorporate a release in their standard contract form which the customer signs.
This release authorizes the photographer to use any of the photos for samples and advertising. These pads are also advertised in most of the photography magazines. It's a very inexpensive investment to buy a pad of these releases and keep it in your camera bag. It's much easier to get a release signed when you take the photograph, rather than to find out at a later date that you have a sale for the photograph and can't remember who the person was or don't know how to get in touch with him. Just be sure you get a release, or don't use that particular photograph.