In Japan, don't give the impression that you are an alcoholic by filling your own glass. Instead, fill the glass of the person who is sitting next to you and then they will reciprocate.
Be prepared to buy the next bottle of wine in Armenia if someone pours the last of a bottle into your glass.
In Australia, you could be expected to buy a round of drinks. 'Shouting' is a custom where people, upon entering a bar, shout drinks to a group and pay for their round.
When in Russia, use your vodka for toasting and don't drink it until a toast is made. Men down the shots in a gulp which women often sip it. And never, never mix your vodka or dilute it with water. If you drain a bottle, place the empty on the floor, not the table.