First we have a lively discussion about whether or not you can show emotion through lines or colors. Some kids seem to just naturally know this and some are totally blown away by it. During this discussion, I have students come up to the board and draw a "happy" line or a "confused" line, etc. If they haven't got the idea by then, this is when it clicks. They also have fun guessing what kinds of lines I'm drawing.
Next, I show them different colors (I use pieces of construction paper) and ask them what emotion that color could portray. Often kids will say that the blues and grays are sad colors while the reds and oranges are happy or energetic colors. I also mention that different tones and shades of the same colors might show different emotions, too.
When you're ready to begin the project, each kid starts by choosing an emotion or mood. Then they create their monster out of lines and colors that they think would portray that emotion. I try to stress that every single line and color should be chosen with this goal in mind. I usually use oil pastels and either watercolors or tempera.
This always ends up being a really successful lesson and my students often remember this concept and apply it to their work later on.
So can you guess what emotion these monsters are trying to portray?