One step at a time
Even the most complex lighting, materials and textures can be broken down into simple components. Here, I’m rendering the light sources one at a time. I start with something around 80 per cent as dark as it’ll get, so I can still see the line work. For each pass, I’m only concerned about adding light. Trace from your light source, don’t light anything that’s blocked, and cast shadows will take care of themselves. In the fifth panel, I’m adding occlusion shadows, and darkening where the horizon reflection separates the land from the sky. Lastly, highlights punch out all those fun little pointy bits.