I thought all of Akash's suggestions were good but a little broad and seemed to involve a lot of reading. And while any budding developer will jump at the chance to expand their burgeoning technical library, I thought there were a couple of items we could add to his list.
The recommendations that made his list are
- Start a project that other people (developers and end users) will use.
- Learn another language.
- Teach someone PHP.
- Ask for suggestions not solutions.
- Use what you read.
I'm particularly a fan of the third one (teaching) - not only does it spread PHP out even more through the masses, but it can really test you on your knowledge (some of those "how do I.." questions can get a bit complex, even from beginners).