Using Travis CI to run unit tests, and then deploy changes to production.
Covers those moments when you're too lazy to use a title.
Improving WordPress' default text search by adding FULLTEXT. Note (2019-04-21): this article is in the process of being updated due to the changes and improvements to MyISAM and InnoDB since early 2013.
Different ways to include templates, and how to keep them all straight.
Quick and dirty tutorial on creating custom meta tables in WordPress