Since I'm mostly a Symfony programmer, I try to follow as much as possible their coding standards, although I do not sympathize with some of their decisions.
There are mainly two points I disagree, for me:
- A line break before braces in control structures increase readability (already happens on classes and methods)
- I prefer to use underscores for the name of variables instead of the camel case notation
Sometimes I forget to follow the standards and it is boring to check back the code and fix it. Fortunately, there are a few tools that can help.
PHP_CodeSniffer is a pear package that analyzes source code and reports the errors.
One limitation of PHP_CodeSniffer is that it doesn't automatically fixes the errors reported, PHP-CS-Fixer for the rescue.
PHP-CS-Fixer is a phar file that complements PHP_CodeSniffer, fixing our source code taking into consideration the standard that project follows.
For last, there is NetBeans, with a simple ALT+SHIFT+F, it automatically formats code. You can download my whole configurations and import them in Tools > Options or use just this file just for PHP and Editor configurations (from NetBeans 7.2).
With these three tools, there's no reason not to adopt a conding standard and implement it in your PHP projects.