Reveal Template helps determine the exact template being utilized to render the currently displayed page in WordPress or those to which WordPress falls back if the theme does not have a template of its own.
The revelations can be shown in several ways: in the site footer (default plugin setting), in a widget that can be placed into any widgetized area, as a shortcode within a post/page content area, or a template tag.
“Theme creep” is what I call it when functionality that has nothing to do with the presentational layer of a WordPress website “creeps” into the theme. What this ends up doing is chaining you to a WordPress theme that seemed like a beautiful and great one for your site when you first saw it. Chains you so that in six months or thirty, when you find yourself wanting a visual change of pace you’re left with a terrible choice: your pretty new look or your properly functioning WordPress site.
It’s a very accurate term for crawling over the boundaries of presentation and into the realm better served by plugins. This always makes me feel uneasy about WordPress themes perfectly suited for the task at hand: what if the development stalls, there will be no support for new WordPress features? What will it take going to reproduce the functionality, presuming that the theme permits to edit the code?
WordPress Responsive Design is a nice collection of tools, tutorials, themes and frameworks that make it easier and quicker to implement responsive design in WordPress.
Whether you’re developing WordPress themes for yourself, for a client, or to sell commercially, having the ability to customize aspects of your theme via the WordPress control panel makes your theme infinitely flexible and many times more versatile and appealing.
The methods discussed here will only apply to WordPress 2.8 or above. There are a number of other tutorials available if you’re using an older version of WordPress
Creating WordPress Themes: Introduction
The first tutorial in a comprehensive series by Shelly Cole on where to start with a WordPress theme and how to enhance it, with lots of handy tips and links.