WordPress Theme Guide
Resources

Do you make WordPress themes for love and glory? Then you’ll want to be sure to check out the handy WordPress.com Theme Guide — this handy guide is chock full of theme best-practice goodness.
Quick Overview
When you’re making things with code, it can be hard to keep up with the learning — the reading and research you need to do to make sure that your work reflects the latest ideas, techniques, and security best practices. Thankfully, if you build themes, The WordPress.com Theme Guide does the heavy lifting for you on escaping, internationalization, queries, scripts, styles, plugin conflicts, and more in an easy-to-scan checklist format. You’re welcome.
Image based on “Remington_Noiseless_Bedienungsanweisung_ 2” by Georg Sommeregger, CC-BY-2.0.