Please help me to light a scene correctly, or better, in the best way. My goal is to make it as realistic as possible.

Actually, I was thinking about global illumination, as I'm using this lighting method very often for indoor-scenes (lightspot on a white plane etc.).
Now as my new scene is outdoor (a person leaning against a house-wall in a bright environment, like the deserts), which lights should I use?
Should I use white planes with a spotlight, too?
Or should I use the light-settings from Howie Farkes' Maple Meadows, as I own it?
Or should I use these skydomes for Tim Payne's skies (never tried this)?
Or just the Carrara-realistic-sky presets?

Or what IS the best way to light an outdoor-scene as realistic as possible in Carrara?

I feel as if I'm stuck with this....

Thanks a lot for your help!!!

~Sassy~