Akash Mehta has posted a list of suggestions he has for developers wanting to move up and enhance their skills in the language:

So, you’re an up-and-coming PHP developer, you’re spending a lot of time learning new tricks and you’re always on the bleeding edge when it comes to using technologies in your web applications. What’s next?

His four answers to "what's next" are:

• Read books, write code.
• Attend conferences
• Take courses and qualification tests
• Watch the web

...with the final one being his most important.