The business of photography like any other business, takes planing, dedication, effort and many other things. With proper planing, research, marketing, dedication and effort you can make a decent living in photography. Is it difficult? The answer is: very difficult.
Not only do you have to run a business, but it largely depends on your skills as a photographer, the subject of your specialization, location, as well as other factors. Once you have decided, that your photo skills are complete, had your photos criticized by those who know, have a large inventory of photos (at least 1000), then you should consider how to market them or rather market yourself.
First of all, deciding on what photo genre will comprise the vast majority of your shots is paramount. Will you specialize in one type of subject: only weddings or only flowers. This approach has relatively a low flow of sales, but when the need arises for your specialty, then you're the one. More generalized photography guarantees a stronger sales flow, but requires a lot more effort also. However publications know that they can count on you for a variety of subjects.
Portrait photography is relatively easy to enter, but requires a considerable up front expenditure. You will need reflective equipment, such as umbrellas, tripod, several backgrounds, props, a complete office, business cards, insurance, tax forms, should I go on?
Portraits subjects are however easy to find. Weddings, birthdays, baby showers, bachelor parties, reunions, births, pregnancy and glamour, boudoir, etc. You should also have several samples to display in your store front and to include in a marketing brochure, even if you have to take the photos free of charge. Nothing will sell you better than your photos. You can do without the office if you can set aside a room in your home to meet clients, do paperwork and work on the shots. As far as pricing, a simple research into your area's photographers will do the trick. Start reasonable and escalate as your reputation and demand grows.
Nature photography is quite well represented, but editors, publishers, publications are always looking for fresh material. Before you submit anything to any publication, ask in writing for a want list which is a list of the publication's most in demand subjects. Also consider creating a stock list of the subjects which you already have on file. Ask for a submissions guidelines and stick to them. Unsolicited material is often discarded, and if lucky, returned to you. Strongly consider writing an article to go with the photos, even better write an article and shoot around it. Publications are always in need of articles and ideas that align with their material.
Think small when starting. Newspapers, small local magazines, calendar companies, greeting cards companies, book publishers, poster makers, even product catalogs are purchasers of photographs. Inquire about submitting materials to them. Don't forget to label your contact information as copyright on any material which is finally submitted as well as to include captions with information about the photograph, such as location, name of the creature, flower, plant etc., scientific name, and technical information.
Submission to photographic stock houses. Many stock agencies require a minimum of photographs to even consider you, usually between 300 to 1000. But there are some that will require much less. In any event, whatever you submit must unequivocally be your best work. Very sharp, accurate exposure, top of the line, not just "slightly" out of focus, but 100% technically perfect.
You will receive the advantage of being represented to photo buyers, and the disadvantage of competition from many seeking exactly what you are. You should strive to make at least $2.00 per shot per year. So a submission of 30, 000 photos should gross you $60, 000 minus your costs the rest is profit. This requires that you shoot a large number of shots per month, at least 1000. Many agencies will also require exclusivity, especially if you begin to gain recognition for you work, so choosing which agency to represent you requires thought.
The idea is to gain recognition first before venturing into the major markets such as National Geographic, which by the way has their own staff of photographers, or Audubon Magazine.
Photojournalism. Many publications have their own staff, but regularly use the work of independent photographers. Look for ways of receiving updated news information of breaking news, look for planned events such as demonstrations, news conferences etc. Approach the editors desk of publications which you are interested in submitting your work to and register with them as a free lance photographer. Many will accept your registration and will look at your material with prior knowledge and since you don't get paid until your material is accepted it is easier for them just to register you. Do obtain a submission guidelines and acceptable formats as many prefer black & white formats. Consider joining a photojournalist association for important updates and leads.
Scientific photography. You will need very specialized material and the know how of the subjects you will be working with. keep in mind that bacterias, viruses and others can pose a health risk and many require a permit before you can get your hands on them. Approach publications the same way as you would approach any other photo publication.
As mentioned before, keep in mind your overhead costs, if your cost estimate calls for a $20, 000.00 per year in overhead, then you gross in sales should be $40, 000.00 per year.
Read plenty of photography magazines, look at current publications, posters, greeting cards, new books to get an idea of what is the trend. Good is also to enter contest whether you win or not, but get your name out there.