Saigon/Vietnamese Etiquette:

https://youtu.be/ixii2i1RRGA

...also, never point the soles of your feet at any Buddhist monks, and avoid sleeveless tanks or tube tops baring armpits at Temples.

***When you hear the gong at the Temple, bow your head out of respect, during the ceremony, where you may be expected to be barefoot, and kneeling on the cushion.***

http://www.lonelyplanet.com/vietnam/travel-tips-and-articles/1375

***For a more formal bow, towards a Buddhist monk, for example, hold each opposing elbow, forearms across ribcage, and bow your head down for a slightly longer count (2 seconds).***

It's good manners for the women to be seated at another table/area, away from the men, for dinner parties, and to get to know all the Buddhist Temples also. At the Temple, try to arrive earlier than meal times, to assist in the kitchens. Bring red envelopes with charitable donations, e.g. checks, cash, if you're interested in supporting the Temples' monks.