Basic Decorating 101 = the Basics - Environments
Nuvera Online
Quick Tip: The sun in real life does not cast yellow light. The light is invisible and refracts and reflects the environment it is in, which is why I normally just leave my sun colour white or off white but change the ambient instead.
Quick Tip 2: Night time shades are cool like blues and purples whereas daytime shades are warm, like oranges and reddish hues. However it can also depend on the skybox you are using so playing with the colours to find what works best for the overall scheme is a good idea.
To change the colour of either the sun or the ambient, click the small colour square beside those words at the top of the menu.