Here’s my process for the Kaguya Hime illustration.

Near the the end, there were a few things bugging me that I fixed:

I realized the moon and stars were taking all the focus of the image, so I shrunk the moon, and got rid of about 80 percent of the stars. The moon is a big part of the story, but Kaguya Hime is the main character, and this is her final moment, so I wanted the focus to be more on her, not on the sky.

I brought the warm colors to the front and the cool colors to the back to bring the foreground forward.

I balanced out the hills a bit more to help them frame the focus (Kaguya), rather than just be a bunch of neat hills in the distance with no purpose.