Have you researched what trade publications the industry`s you wish to market to frequently subscribe to? The reason I ask is because you might be able to negotiate with the trade publication`s editor to provide a featured photo in exchange for being mention in an article or better yet submit a press release to the trade publications with a "why it should matter to you" angle which highlights how your photography enhances brand image, educates consumers/their target market, etc.
Another options is to visit your local library and ask for reference books on publically traded corporations. At my local library these reference books are in the finance/investment section. The information within those reference books typically will tell you who the corporation leaders are, their salaries, their board of directors, etc. Plus they often name the subsideraries held by the parent corporations. Once that information is known then you can generally go online to read either the subsidiary or parent corporation mission statements, and value statements. This would allow you to customize your presentation to fit their public image and market it to their marketing directors/public realtions department.
Another good source to review would be Crains Book of List or similiar book of lists publications.
I second the sugggestion to look into to the Trade Publications that target the industry that you would like to work with. This is an excellent resource because it targets your niche market and only your niche market. If you decide to advertise in the magazine you know that you won`t be wasting a dime on people who are not in your market.
Second you can stay up to do date on the trends in the market which may give you hints to ways you can tweek your services to meet the particular trend.
*** This is a very difficult task. Staying relevant to an evolving industry or market is difficult but is essential to your survival and profitability. So paying attention to trends will allow you to stay ahead of the curve and adapt to your customers needs.
Last you can find out who is using services like yours and other companies who will want to use services like yours.