Web Programming Philosophy
Easy Code Maintenance. Not everyone manages their own code. You don't want other programmers to think you're lazy, or drunk. Code should read as easily as possible in english (very difficult!). If you want the code to "print the welcome message if the user is logged in", the code should (within the bounds of sanity) be "if( $user_loggedin ) echo htmlspecialchars( $welcome_message );". As non PHP programmers will notice, this is not always easily read, but it should be as easy as possible.
Object Oriented Programming. PHP is not the best OO language in the world, even PHP 5. But I firmly believe that OO programming begins in the programmers head. I think that since web requirements change so frequently, we need to program (as much as possible) for extensibility. OO design a good starting point.
Requirements. Requirements should be spelt out as much as possible in the beginning of a web project. If this is not possible, at least the spirit of the requirements should be clearly communicated to the programmer. That said, I firmly believe its impossible to get all requirements from the client. So how do we balance the need for requirements against the changing needs of the customer? I believe during the course of the project, small development iterations should be adopted. And this necessarily means customer participation. At the end of each iteration the customer should present to give feedback, even if the technical mumbo jumbo presented confuses him. This reduces the animosity between developers and clients that is present in most web development projects. Programmers understand more and more the non-technical concerns of the customer, and the customer understands that web programming isn't just a matter of cut and paste, and sees that the programmer actually cares deeply for the customer's website.
