I've been researching ways to make an income with photography and effective business models for marketing and 'branding' of one's photos.
Quit simply, stick to one thing, and do it well.
Two fantastic examples are Clark Little and Martin Wuagh. They focus on unique photo styles with a consistent subject and theme, creating a catalog of similar images. This gives them the label of 'expert' on these subjects, and when marketed correctly their photos can create a comfortable income through licensing, print sales, and advertisement usage.
Clark Little is a surf photographer, who specializes in photos of waves, almost all from the same perspective. He's spent hours and hours in waves photographing them, and he's GOOD at it. He's only been at it since 2007 and his images have been featured on Today Show, ABC World News Now, Paris Match (France), Hana Hou (Hawaiian Airlines) magazine, and Surfer magazine.
Some of Clark's photos:
Martin Waugh takes high speed photographs of liquids in motion, mostly water drops.
He was recently featured in the May edition of Money magazine, on his switch from working full time to being a photographer full time. His work has been used by Smirnoff and Coca Cola, and covered in Entrepreneur Magazine and Discovery Channel, along with a number of photographer magazines.
Some of Martin's photos: