The Tips in detail

 "Look at what things look like in the real world."

If you are designing objects it pays to know how they really look. Open your eyes and look. Compare to your image. What does not look "real"? Why? Also the teamplay of form and material is a "must know" to get good images from your renderer.

Light also plays a keyrole in how your objects appear in what you get from your renderer. You will be able to hide certain flaws by proper adjustment of your lighting, but when animating you can't always bet on this being possible.