Looking at your render too long without a break is one of the biggest pitfalls that hinder even the best artist. Sometimes the best solution is to simply walk away from your computer for a few minutes, or just step back from your screen a few feet.

There is probably no better tool to routine out bad renders than looking at your render in reverse. Reversing your render allows you to see your rendering in its proportions with a fresh eye. You can mirror you rendering in Photoshop, or simply print it out and look at it from the back side, through a bright light.