StoneNYC, you say you won't always be using lighting. Assuming you do not mean photographing in complete darkness, pay attention to your background and flare. Generally speaking, a low-key portrait against a black backdrop has less flare and more detail, ie. wrinkles and everything that adds that certain character to a face, hair etc. High-key, against a white background, or with a source of light close to lens axis, will cause fair amount of veiling flare, which softens a portrait a good deal. Try looking at portraits around you, and you should notice this.