Someone posted a list of things to do (or not to do) regarding protocol in Bali, including, I think, "don't touch anyone on the head" and"don't raise your voice/argue loudly in public". Haven't time at the moment to find post - but thought Newbies might like a few more tips....
Don't use your left hand if you shake hands (left hand used for hygiene by Indonesians, so considered unclean)
If beckoning someone, don't crook your finger - put your hand downward and use all fingers to make beckoning motion.
Try not to put your hands on your hips - seen as aggressive.
Ladies - do not enter a temple if menstruating, and all people should cover themselves well - especially the area between the waist and knees - no short shorts!
Don't get cheesed off if you are asked "where are you going?" - it is almost a rhetorical question, and you can be vague and say "jalan jalan" - they are just being polite (like "how are you going?") and not trying to intrude on your business.
If passing between two people talking on the street, it is polite to duck slightly or say "Ma'af"
While Indonesians, especially Balinese in tourist areas, are quite used to our ways, I still think it is important to show respect to our hosts.
Most of all - have a wonderful holiday!! :)