I tried messing around with cell shading, loosely following this tutorial: http://www.youtube.com/watch?v=URYgrlNQmU0. I set up everything in the materials like he does and click Render, but it doesn’t show me the settings I placed… instead, I just see the normal shading applied to whatever color I chose. This shading stays exactly the same regardless of how many lights I have in the scene or where they’re placed, and even when there’s no light at all. 
Perhaps I changed a setting some time ago by accident that turned it off or something, but it’s quite irritating that I can’t get things to work properly. Any help would be appreciated!