While I'm not a fan of certifications and the sort, it's definitely helpful for a novice developer to have a scale to measure himself against. Something that answers the question "what do I need to learn?"
The guys from clean-code-developer.de do a decent job of defining stages and methods to assert yourself. I would suggest to anyone to try to follow it for a while. It's harder than it seems.
When it comes to PHP development, there is also phptherightway.com with a nice collection of best practices and tools. Anyway, this is how my list of skills and tools would look like:
Wanna talk about it? Tweet Found typo or wanna add something? Edit me