For the photographers looking to get into portraiture, consider this infographic with specifically marked areas and field notes for you to pay attention to when looking at a subject. This infographic emphasizes what you should be mindful of for an upper half portrait. When the other half of the subject is involved, then there is much more to worry about. In general, these are the areas that we always look at when shooting a portrait, but something there can be much more.
Enjoy!