I've used natural (sadly, natural = rough and itchy!) fabrics to try look as rustic as possible without being untidy... mostly linens and cottons, with a touch of burlap.
I went for the pirate hat version, because it's been a hope of mine to cosplay someone with a pirate hat, although I never thought it would be like this! I made the hat from a thin faux suede, with foil lame appliques.
Any questions, yell out~
"Best Group" (with 13-Zer0's March) at Supanova Cosplay Festival (Brisbane) 2010