Hi Laura,
Using one single light to create a portrait of a really good way of learning how light works. As you move the light about you can see the shadows changing on the subject's face and you soon learn what works and what does not work.
To get critical of this image, the first thing that I notice is Michael's forehead; it is really big and really bright. There are two reasons why this has happened.
To start with, you have placed the light source too close to Michael's head. This has created quite a hot spot on his forehead and as a result we have lost some of the detail in this part of the picture. Ideally you want to have the light at least a metre or more away from the subject so that it spreads evenly across the face. Moving the light back even further and placing diffusion material between the light and the subject will also help soften the lighting on the face, although this is more an option than a preference.
The second reason his forehead appears rather large is that you have actually photographed down on Michael with a rather short telephotos lens. In this instance I would have asked Michael to lift his chin up a bit towards the camera, or I would have used a slightly lower camera angle.
In the example below I have used the clone tool to ease back the highlight on the forehead and then used the lens correction tool to widen the chin while narrowing the forehead. I have then cropped the image to add some black negative space on the left-hand side of the frame.
That's all there is to it!
Hope you get to do some more portraiture soon.
Cheers, Anthony.
Image Doctor's edited version
