Shredded hat sounds good. You could build off of that and go for a zombie pirate next Halloween. All that really requires is face paint and slightly more tattered clothing. (Maybe the glow in the dark skeleton body suit, a la Tigger's gloves, if you're feeling adventurous).
You've got the right idea on how to assemble regalia, though, that much is obvious. Just shop around thrift stores and costume shops, and stay away from full set costumes that can't be disassembled.
Reminds me, I should post those pictures. I'll have to edit out some faces, first.