Portrait photography is for the most part about character and understanding how to generate character in a photograph is not something that can be learned overnight. Portrait photographs require relaxing the subject to the point that they feel you have got something out of them that no one else can. In some ways this is one of the most difficult tasks when taking a photo. Weather shooting a portrait for staff photos, actors head shot the shot requires a certain level on candid photography which brings in the balance of timing and technical knowledge. Plus the subject needs to be relaxed and brought to their element which is a skill that usually takes photographers years of experience.