As for #6, I'd go as far as "NEVER use include, period." I've seen about 1 actual use case out of the bazillions out there; almost certainly, require() is the droid you're looking for.
I'd also add a #10: Use E_ALL | E_STRICT , and don't ignore it. PHP is trying to tell you of many problems, shutting it up is not the right answer.
I'd also add a #10: Use E_ALL | E_STRICT , and don't ignore it. PHP is trying to tell you of many problems, shutting it up is not the right answer.