The simplest way for photographers to sell their own images is to establish a personal website dedicated to a gallery of their own work. In recent years this has become very easy to achieve. All a photographer has to do is purchase one of the excellent and widely-available standard websites, complete with an image gallery and a secure means of making payments, and upload the images and necessary descriptive text. This approach has become very popular so competition in the field is inevitably increasing.
Another similar approach, which is probably more economical in the longer term, is to establish your own website either on free web-hosting space or by renting space on a commercial server. For the cost of a suitable web-design software package and a bit of work, it is relatively easy to establish an effective gallery-based site in your own image. This approach is more flexible because the photographer can grow the site and change its design at will.
Most photographers start by selling prints and, if successful, expand into other fields such as running an image library or organizing photography holidays based upon an established photographic reputation. Those considering any of these routes should first spend some time looking at the material already on offer on comparable sites worldwide. It soon becomes clear that the quality of the work on offer ranges from superb all the way down to awful. The safest initial option is probably to sell work related to local subjects because the photographer then has the significant advantage of convenient access to his or her subject.