Everyone works differently. It ultimately is a good idea to keep your drawing development in line with how you think. I work in different layers, but many artists like to do a general sketch on one layer to get the idea down. It always starts with a sketch, though. Even paintings all have pencil sketches on the canvas at some point near the beginning of the painting to help guide the colors and composition.

Composition is a huge part of it, and lighting is just a sub-element of that. Think about what kind of mood you want to say in your piece, and treat your drawing like a still frame from an Academy Award winning movie. Ask how you can enhance your storytelling by how you compose the image, and ask yourself what kind of lights will further portray the message you want to get across. Think about light sources you can use - flourescent lights will cast a greenish hue, tungsten lights will cast an orange hue, outside light will be white light, with a blue ambient fill light if the sky is blue, and a gray ambient fill light if the sky is gray. Shadows will never be black except in the areas where light cannot ever reach. And light adds a third-dimension to a two-dimensional drawing. You're able to get a better idea of how a simulated 3D figure could exist in a 2D space when you apply shadows, which are a direct result of light. The light could be from a candle, or a flashlight. It could be from a lava lamp, or even lava itself. The light could be from the moon, or a midnight sky, or maybe the light is from a lantern, or from a cityscape reflecting on water, or lighting up the atmosphere with a glow. Treat the light as a storyteller. Treat the composition as the cinematography, to sell the situation, to get the idea down, and to make the visuals interesting. And treat the background as -the- most relevant detail in the image, because the background gives the -setting-. Just like every short story, fanfiction, and novel always establishes a setting in the introductory scene, so you have an idea of -where- things are going on, treat the background the same way. Always do a background, even if it's just curtains, or a grassy fields placeholder just to insert a horizon line. It makes your drawing relevant because it tells a story. It makes it -memorable-.

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"Don't be sad because it's over. Be glad because it happened." ~ Dr. Seuss

"We make a living by what we get, we make a life by what we give." ~ Winston Churchill