This idea of black and white landscape and colorful sky has been floating around for a while.
The idea of greyscale against color is beautiful.
Draw a landscape on the bottom half of the paper.
Add depth and space with layers.
Out line with black marker.
Add pencil shading if desired.
Before and After pencil shading
Make a colorful contrast.
USe watercolor techniques to make a colorful sky. it can be a sunset, a starry galaxy, or aroura borealis, or something from you imagination.