Your Main Job: Follow the Bride
The main focus at any wedding is the bride, so make darn sure your main focus at the pre-wedding, the ceremony, the formals, and the reception is the bride. Follow the bride just like you would follow the quarterback if you were shooting a football game. Especially if you're going to be selling these photos as it will be the bride (either directly or indirectly) that will be buying the prints. So make darn sure that she's the clear star of the show (photos of Uncle Arnie at the reception don't sell well, if you get my drift).