During the process of creating my first public WordPress theme one thing was very important to me – I wanted the theme to be useful to as many people as possible. To reach this goal, I knew that I would need to make sure that my theme could be used in any language. Luckily, WordPress core provides a few different functions that makes this pretty easy to do. If this is a new topic for you, please read more about Internationalization for WordPress Developers in the codex.
Oldie but goodie guide for basic Terminal commands.
Dust-Me Selectors is a Firefox extension that finds unused CSS selectors by inspecting your stylesheet and comparing the rules with the elements in your markup.
A must-have for your webcraft toolbelt.
Version control is a key part of a successful software project, and we use Subversion heavily at Automattic. All our themes, side projects, and even PSD files go into SVN repositories.
We often talk to theme designers that are getting into more advanced theme development who need a quick crash course on using Subversion. As part our tips for version control we recommend keeping a handy reference guide at your fingertips for common Subversion commands.