First up, you have to master the New Zealand accent. You must sound pleasant, earnest, and a bit dim, and you should probably mumble, because you are at all times discreetly dissolving that giant lump of mutton at the back of your throat. You should also speak with a rising inflection, so that everything you say sounds like a question. (Certainty is terribly impolite.) And keep your lips as close together as possible when you talk; remember, you are trying to keep the flies from entering your mouth.
This man’s excellent impression of Prime Minister John Key will give you the idea:
Selecting an appropriate topic of conversation is important. You may talk about rugby, the road toll, mangrove swamps, birds, pig dogs, and the rain. And speaking of rain, you should memorize “Rain,” the nation’s most beloved poem.
Finally, you need to learn the vocabulary. If you are fluent in Kiwi, you will be able to parse a sentence like this with ease:
When Bruce and Tasha hooned it up the boohai, their ankle-biter got crook and chundered in the chilly bin each time they went over a judder bar, which made Bruce throw a wobbly.
(Translation: When Bruce and Tasha drove quickly and recklessly to a remote place in the middle of nowhere, their small child became sick and vomited in the cooler each time they went over a speed bump, which made Bruce lose his temper.)
Also note: in America, something is “quite nice” if it is very nice indeed, while in New Zealand “quite nice” is a gentle way of saying that something is not very nice at all. If a Kiwi tells you your banana cake is “quite nice, eh?,” I’m afraid your banana cake is rubbish.
And never mention toilet paper in polite company. Call it skindywoo, as in “I just had an epic chunder in the back of your van, mate. You got any skindywoo?”