If you want a good way to get better at PHP or just about anything for that matter, here it is. Get on a PHP (or whatever else) forum like this one, and start answering questions. There is no better way to learn something than having to research how to get it done, some quick testing, and then teaching somebody else how to do it. There's tons of online forums with php and other development topics. You don't need to be an expert to answer somebody's question. Even if your answer isn't the best way to do something, you will most likely find a healthy array of resolutions and a better way to do something yourself. Don't be scared to contribute just because you started programming a week ago. As long as you keep an open (and sometimes humble) mind, nothing bad can come from it.
Agreed experience is a huge factor in learning PHP, and gaining experience from forums has the added effect that people can correct you and provide optimal solutions, you may have never thought of. I've only been learning PHP about 3 weeks, and I reckon I can provide some sort of solution to about 75% of topics posted on here, only because I am active on forums, and read up on tutorials. Don't just be the question provider, be the question solver, it's a lot cooler