It's possible it's just lighting you set up for a beauty shot there, but try to think of it like how you might light it in real life.  Often it seems like people aren't sure where to put this light and will toss a light wherever and often in places that make no sense. In a case like this you may want to tell yourself a bit of a story if you're trying to get it to blend into a scene nicely, and figure out where this light would be coming from in the scene.
Your key light is your main light source. I will start off on the concept of 3-point lighting, as I understand it. The three light points are typically referred to as Key, Fill and Back. We will cover this all again when we start lighting, but first we have an overview so we are working with the same mind set.
This is hopefully a tutorial covering some basics of lighting in Maya, utilising Mental Ray. I made this tutorial for someone in a forum and tried to replicate their scene to better show them how to control their lighting. So while I wish I had some more detailed models in there to demonstrate with, such as the head, I used what I could find that was shaped most like the stuff in their scene, rather than what looked best. I don't consider myself great at lighting or anything, but I noticed a lot of people seemed to have issues with artefacts in their shadows, or lighting set ups that make it looks like it has artefacts, or they can't soften their shadows, so I figured I would try to help out. There's probably some better ways to do some of this stuff, but this is what I have to offer, and hopefully I'm not providing any incorrect information.