Some night light tips:
Moonlight is the same color as sunlight (since it reflects off the Moon, which is quite neutral in color). Hollywood has people thinking it's bluer at night. You can go with that or not.

Actually, what happens is that in the dim moonlight, your retina's cones (color sensitive) don't have enough light energy to do much for you, so your rods (monochrome) take over - except for the light sources themselves and any well illuminated surfaces, of course.

Street lamps cast interesting shadows from their internal parts. Here is an example from my training e-book for digital artists - i used a point light in each lamp and located it as high inside the lamp as possible to get max shadows.

Vue 5i has a curve for light sources which lets you control how far from the source the light starts to be visible. With this you can but a light source inside an opaque object and still have light coming from it outside the object. It's great for how wide a searchlight or car headlight beam will be as it emerges and such.

This control is in the Lighting & Shadows control above the object hierarchy list when you select a light source.

Dim light can be pretty contrasty (low signal-to-noise-ratio or dynamic range, since you are near the threshold of sensitivity of the eye) so you may want to use a pretty high contrast.

You can get extra drama by using Volumetric Illumination at night.

Like any other art challenge, it really helps to go and observe keenly. So, if i were you, i'd take some night time walks and get a very good look at the real thing.

Cheers!

_jc
Art-Head-Start.com
Training e-book for digital art students