Here is how I arrange floating orbs of light to create a city environment at night. (Click on the images for a larger view)
Jumping straight into the biggest and brightest lights, and identifying the various colors.
The darkness floods in!!! Alizarin Crimson and Ultramarine Blue gets pretty dark as the paint thickness builds up.
I bring in the other lights, such as the second brightest lights, and smaller sparks. Random light reflections also emerge.
Wires are strung, the red lights glow redder, but the whites still peak through...