Software Development
Professional PHP
It's important to remember what sets a professional PHP developer apart from the pack that floods your average help channel.
Too often I run into reviewing or helping a "professional" developer, and I can't help but mutter "you're doing it wrong..."
Nice Article on Software Development
I found this article The Future of Software Development and found it rather interesting. As it compares the older Waterfall Model of development, to Agile Development, and why it works.
Take a look, and be prepared to be informed.