For most times portrait photography is an agreed image session between the subject and the photographer. It is a medium to portray expressions, personal traits, culture, traditions, moods, and character of somebody.
There are ample of opportunities and poses to use. You can opt for either directing the poses or go for unposed, candid shots. At a professional portrait shooting, you have to please your subject and portray the subject as requested. Not many opportunities, in this case. For me as a freelancer, imagination is the limit. I like to go for candid shots, often for experimenting and trying to capture movement and activity of people around me.
One critical issue with portrait photography is to get hold of natural looking poses. The essence for me lies in capturing shots which represent the character of the subject creatively. I use soft and diffused light to get a certain look I fancy.
I find that portraits can effectively benefit from elements like action or movement. This is the edge some pictures look more professional and outstanding. The context and the surroundings help set a mood of the photograph. The incorporation of elements like fog, snow, clouds, fire, etc. helps in creating an atmosphere which goes a long way in obtaining a photograph interesting and draws the viewers attention.
As a final touch, I include and embrace post-processing. Sometimes subtle changes, sometimes big one. A good portraiture does not only reflect and interpret the actual person but also portrays your art and creativity as a photographer.