This is one thing I learnt (a bit too pro for most people, but interesting)
Setting up side flashes to direct light at the subject from the sides gives a rounded view because the light doesn't come from the front only.
Check this out:

See how the sunlight comes from behind, to give the effect, but also how the driver's face and the front of the buggy - which should be dark because the light from the sun is behind - are lit up nicely.
This is how he set up the shot:

Here's a real serious tutorial for those interested: http://www.thewonderoflight.com/articles/?page_id=114