fall wedding attire

I'm attending one of Kevin's best friends, Sam and his finace, Alisha's wedding at the end of October.  Being the girly girl that I am, ooobviously I have already started thinking about potential dress ideas.  Here's my problemo... I have never been to a Fall wedding, so I'm not exactly sure what kind of dress is appropriate.  Clearly I wouldn't wear a pastel color or anything, I'm talking more of the style of the dress.  Is strapless appropriate if it's the right color (maybe with a wrap in the beginning)? One shoulder? Cropped sleeves?  Are straps a must?  Any suggestions would be greatly appreciated!  Otherwise, I'm going to have to go with a bag over my head. : )

Just like this chick... it would be my "I didn't know what was appropriate so I wore this" look...

 NOT PRETTY

p.s. This is the first day I can bend my finger more that a forth of the way!  It's still pretty bruised, but definitely NOT broken. YAY!

check out how swollen it is... I don't just have giant fingers, I promise!