I agree with everything David said, he is clearly knowledgable in this area.
Long lens, some type of softening filter (if needed), diffused lighting in most cases (umbrellas, strip-lights, white reflecting material, etc.) are all ingredients for good portraiture. I also use yellow or green filters to control B&W skin tones (haven't tried orange, though).
One note of caution: wide faces need more contrast than narrow faces to avoid enhancement of these characteristics, unless that's your intention.