While Sheldon is responsible for the general outline, guidelines, prizes and told you about them in his post, I will now tell you about how the themes are rated and give you some tips for your themes.
The contest is closely linked to the imminent release of PHPFusion 7. Consequently, a very important criterion for the rating of your theme submissions will be how you used the new features of PHPFusion 7. Custom head tags, output handling, the jQuery javascript toolkit and other new features provide new possibilities to influence the layout of your themes. Do not overuse them though, overuse could what we call sensory overload and take away from the main purpose of a site. Your theme(s) should not become a pure tech demo, but you should use the new possibilities you have in a reasonable and clever way to enhance the content and features of a site.
Themes provide the visual interface of PHPFusion sites. Thus the look you create with images and code will also influence the rating of your theme submission. Again, be careful not to add to many images or effects and keep an eye on load times and usability.
The next criterion is the code quality of the theme. The theme PHP code and JS code should be readable and should not produce any errors, you should avoid redundant CSS and try to stick to the W3C HTML and CSS specifications (note: Core 7 is XHTML compliant and therefore to be fully compliant your theme will need to follow the same DTD, use the W3C validation utilities at http://www.w3c.org ).
The last rating criterion is called creativity and sums up the other criteria. You will get a high rating here for new or interesting approaches of theming the site elements or interesting new features added to the theme. Remember that div layouts are now possible in the Core 7 theming structure.
Read more for more details on the weighting of the criteria, the community vote and the calculation of the final rating.
Note: Final Submission Date will be 1 month from today's posting date (end date: July 28th). Cheers.