Unless you have been actively involved in the design, advertising, or marketing industry, chances are that you need previous commercial photographer services quite slim. Even the first time and last time many people made contact with a professional photographer were when they got married.
The professional photographers are proficient in various work and services ranging from product photography to real estate photography to food photography and aerial photography. You don't need to be an art critic or executive flying ads to make good decisions about what makes photos that are great or bad.
However, if you are a small business owner to medium, you may not have a budget to have such luxury and must make such creative decisions themselves. It leads me well to my first consideration:
Image Source: Google
Budget: Commercial photographers are expensive and if you expect to find a great one to fire your entire product for a few pounds/dollars, think again. Be realistic about what you need for the photographer and then set your budget accordingly.
Genre: Try to stick with photographers who are accustomed to working in a commercial environment and if you need photography of a product of a photographer who photographed many studios still alive e..c. Many photographers are happy to make a choice of photography genres but most will admit having their own specialists who feel the most comfortable.
Style: The artistic style of the photographer shooting in May or may not be relevant to your work. If you only need some generic package packages, for example, the photographer's style doesn't need to be a great concern.