I'm new to this design thing as well. But I'm science nut so this stuff really gets me goin'
The principles are pretty easy and the formula for heat conduction will show you what makes heat transfer better. The formula explains why Cathar's design works so well. Here's the formula, beyond it it's a matter of inovation, and Cathars looks hard to beat, but all designs can be made better-
Heat Conduction Formula
Anything that makes the left side of the equation bigger (ie: thinner barrier, more area) will help.