Knowing how to light, pose, and compose a portrait is only half the battle. To create a successful final image, you also need to have strong editing technique. If you would like to learn how to properly edit a portrait, check out this fantastic video tutorial that will guide you through the entire process, including frequency separation, dodging and burning, and color grading.
Coming to you from Eli Infante, this awesome video tutorial will show you how to retouch a portrait in Photoshop using a variety of techniques and tools, including frequency separation, dodging and burning, Gradient Maps, Selective Color, and more. Frequency separation sometimes gets a bit of a bad reputation, but that is more because it is so powerful that it can be very easily overdone, but when it is done with a light touch, it is a very effective and useful tool. On that same point, in general, it is generally a good idea to err on the side of doing less when retouching a portrait lest you end up with a result that looks overly artificial. The best way to do this is to zoom out often and to step away from your computer for a minute or two when you're done to allow your eyes to reset, then to reevaluate the photo one more time before you export. Check out the video above for the full rundown from Infante.
This is a good tutorial on how to use a range of tools without going too far.