Over on the O'Reilly Network this morning, there's a new article from their local PHP guru, John Coggeshall, about some common style mistakes that people make, and how to benefit from a little "PHP Paranoia" in your apps.

With some PHP basics under our belt, it's time to introduce one of the most important things when writing web applications: security. I don't mean just protecting credit cards or other personal information. Rather, I am talking about writing secure, solid code from the very first line to the very last. With this topic, which I call "PHP Paranoia", I intend to teach you not only the function calls necessary to accomplish a task, but also the thought processes and practices to do so safely.

Some of the common things he mentions are avoiding optional config directives (like short tags), avoiding impropper array syntax, and not using function return values directly. Things like this can not only help you make your code easier to update in the future, but also create a more "solid" environment for your applications.