I don't believe in "rules". I think sslechta & racyc pretty much nailed it - if you can get some tools to equip yourself with, great. But my opinion on Pattison (I'm not a fan and think he's horribly overrated) is based primarily on this truth:

"I've also found that quite a few Berkley grads become fixated on the rules and can't cope with things like not following trad western chord progressions etc."

I taught a commercial songwriting class at a college locally (until they cancelled the program) and what I always told the students was "the only rule is that there's no rules". Clearly that's an exaggeration, but the point was to get them to think outside of the box and not get locked into bullsh*t like syllable counts, perfect rhymes, etc.

FWIW, all the truly exceptional writers I've ever known and worked with never read a single book or took a single course on songwriting, they just did what came naturally. The organic approach doesn't just work for food. ;-)

http://www.rogerbrownsongs.com
http://www.nashvillesongwriters.com/roger-brown