I would say that photographic technique and postprocessing go hand in hand in order to make the most of a portrait.
Off-camera flash is, imho, an important ingredient in making a good portrait. I like to place the flash at about a 45 degree angle to the subject. I also use either a home-made softbox or umbrella.
Once I've captured the portrait, I use this photoshop action in postprocessing:
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Be sure to read the tutorial if you use this action. The action has four steps: Soften skin, sharpen eyes, brighten eyes, and vignetting. You don't have to use each step though, just use the ones you want. The brighten eyes step is also useful for whitening teeth.
The key to this action is subtlety. After applying each step, I adjust the layer opacity to anywhere from 20 to 50%.
Give it a try, I think it works great.