Since most landscapes tend to be "daytime" scenes, I like to throw in a "nightscape" once in a while. This is one I did in a class very recently. Because night scenes are rather monochromatic in the colors, the values are the important factor. The key is in getting the overall mid-tones established so that the lights and darks can be balanced with them. Although there are still strong light and dark contrasts in this piece, the majority of of it is mid-values and the subtle increments between those.
This was a simple color palette comprised of Ultramarine Blue, Dioxazine Purple, Ivory Black, Titanium White and just a touch of Cadmium Yellow Pale ( which yielded the green for the eye of the wave when mixed with the blue )
If you want to try something different and give yourself a challenge at the same time, try a night scene!