Difference between a good portrait photo or headshot and an amazing one is almost entirely down to the quality of light. Yes the background is essential, and so is the body language, but if light is poorly directed and its quality (hard, soft, diffused, focused, etc.) is not complimentary to the rest of the image then all will fall apart. To create an outstanding image you not only have to know how to operate with light, but also why and when to use specific techniques that will result in a natural and undisturbed energy flow through the whole image. In other words, when you look at it it has to feel natural, and you should not see any element that stands out to the extent that it dominates the photo in a negative way.
When I work with a new model and I have no idea how to light her face yet, I experiment and search, the I discover and conclude. Everyone has a different face features, and they come with various types of personality. This will require different lighting each time for each person. If you mount your light on spot A and place yourself in spot B every time you shoot, only because it is your safe spot and you know you captured decent images last time and 100 times before it, you will learn nothing and remain medicore at best. Think of your photography as a boat and your model as the wind. Set her lose and don't force posing, and let her steer you in a general direction of what she feels is natural in terms of positioning and body language. Then become a sail and adjust your course. Sailing against the wind is possible but why on earth would you do that.
Light should not only direct the eye around the photo but it should be an integral part of the entire composition. If you think about it, there would not be a photo without light. On the other hand even the most amazing model placed in a bad light will look terrible. So you have to be sensitive to body language, yes, but poses and angles that you capture those poses from have to be in symbiosis with the light and its quality. Do not copy and photograph what you can, capture what you feel you should in a given moment. Do not photograph what your eyes see, but follow your heart instead. If you appreciate the subtle differences of light angles, intensity, direction, and so on, your portraits will look much more rich, defined, and peaceful at the same time, regardless of how dynamic the message or subject of the photo is.
Editing is essential for your progress, and I cannot stress this enough. Forget Lightroom and leave it for lazy people. Diving into Photoshop will not only allow you to refine what you have captured in much better and more professional ways than Lightroom ever could but also will do something outstanding- it will slow you down and let you gaze at the image for longer time. You will improve your sense of composition, lighting, understanding body language and help you to narrow down and target your own shortcoming as an artist. Just like a tripod is great for studying architecture photography, Photoshop is amazing for improving your portraiture. Do not mass produce your images but create them. Not only that, if you start working with frequency separation techniques, which are the only way to professionally edit a portrait image or a headshot, you will discover how you can fix issues with shadows and even reshape face features. This is a superb way of learning the light and how it works.
Contact me directly for one-to-one online photoshop tutorials via desktop sharing.
Portrait photography service, Tokyo - website
Photography workshops in Tokyo: http://www.ryuurui.com/photography-workshops.html
Hire a photographer in Tokyo: http://www.ryuurui.com/hire-a-photographer-in-tokyo.html
Photo blog: http://www.japan-in-photography.com/
For more tutorials and how to videos check out my photoshop and photography tips and tricks YouTube channel: https://www.youtube.com/channel/UCEOVGZ2rpLhR7gSPvaexxxQ