Do negotiate your taxi fare (or ask the driver to turn on the meter) before
Don't be surprised if you're called "Darling" or "Honey" in the Bahamas. It's as common a greeting in the Bahamas as "Mon" is in the Caribbean.
Don't plan to sunbathe nude or camp on beaches: These are illegal activities in the Bahamas (though topless bathing is tolerated in some areas).
Don't worry about changing money if you're a U.S. citizen. The U.S. dollar is on par and accepted along with the Bahamian dollar.
Do experience the less touristy side of the Bahamas: Travel between islands on a mail boat. Your companions will be Bahamians (and sometimes their goats and chickens).
Don't expect to find full banking services on all islands. Make sure you have enough cash or traveler's checks if you go beyond Nassau or Freeport/Lucaya.