I've recently been shaking up my coding habits and have been toying with various approaches to coding style... things like using a space between method call parentheses and the parameters they contain, how to deal with multi-line array definitions and method calls, etc.
I'm wary of creating my personal flavor of everything, though, and want to skim through some well-regarded "authoritative" style guides. Which ones should I look at? I've had a hard time finding much other than the Zend guide.
The PHP Standards Recommendations by the PHP Framework Interoperability Group are a good resource. AFAIK the standards are highly regarded. They attempt to be a collection and unification of what different frameworks have decided to use as their own standards.
I would say for basic PHP coding, especially PSR-1 and PSR-12 are well worth a read.
PSR-2′s purpose [was] to have a single style guide for PHP code that results in uniformly formatted shared code. [The PSR-12] specification extends, expands and replaces PSR-2, the coding style guide and requires adherence to PSR-1, the basic coding standard.
There are several accepted standard recommendations.