Erika Heidi Reinaldo has made a post over on her Coderwall page with a few helpful hints for the budding PHP developers out there about things to investigate and learn to help further their knowledge of the language.
This post is a collection of things that I consider important for people who are starting with PHP, based on my experiences with this language through the years. PHP has considerable evolved in the last years, thanks mainly to the community efforts. [...] As a downside for the language evolution, as things change, tutorials and practices might get deprecated. So we have a lack of good updated tutorials for beginners.
She includes some great things for new developers to look into including a recommendation to "learn the language, not a framework" and exploring git and Github as a collaborative workspace to both share your own work and explore the work of others for helpful hints. She also makes a recommendation that can help more than most developer think - get involved (contribute to projects or meet with other developers, online or at something like a user group).