5. Make sure you're on the same page about bachelor/bachelorette parties.
Monica and Chandler decided to skip the "silly tradition," but the girls later surprised Monica with a bachelorette party. Joey wasn't too pleased when he found out he could've planned a real bachelor party for Chandler, and the postwedding "bachelor" party didn't exactly go smoothly.
6. It's OK to have two maids of honor or best men.
While having Rachel and Phoebe duke it out to be Monica's maid of honor made for good TV, there's no reason to do this in real life. It's perfectly acceptable to ask two people to share the role, like Ross eventually did for his (ill-fated) wedding to Emily.
