First you decide where you want the people looking at your picture to "see" from. Like an audience in a movie theatre. Do you want them looking up, down, or straight at your picture? Do you want them close or far-away? And then you draw...

Next you start to add color. Color is figured out by thinking about the time of day. If you watch the same thing outside all day... from morning into night you will see that the color actually changes depending on the sun or moon! It's pretty cool.