1. Do not read underneath coconut trees
When I was in Tonga, I spent much of my time there reading underneath coconut trees. While under the trees, I felt like my holiday was everything a Pacific Island holiday ought to be ... until a coconut fell from the tree I was reading underneath. Lucky for me it landed about half a metre away, but the thud the coconut made when it hit the ground was sufficient for me to quickly realise how bad it could have been if my head had broken its fall.
2. Be careful to use the correct words when speaking a foreign language
While living in Italy I muddled the words for "happy" and "easy". I only realised my mistake after meaning to announce that I was happy to some Italians and all of a sudden a lot of the young guys wanted to be my friend (or so I thought).
3. Don't use a swearword unless you understand the severity of them
Swearwords in other languages can sound like gibberish, and lack the recoil factor bad words in your own language have. I will never forget the look on my history teacher's face in Italy when I used a word that I thought was the Italian equivalent of "damn".
4. Getting lost can be fun
Even if it leads to extreme stress and frustration, you can find the coolest things that no Lonely Planet will ever write about.
5. Don't assume that you speak the same language as other English speakers
I got yelled at once while waitressing in the USA for not fetching someone a "slide", and when I looked confused the yeller screeched (all the while resembling an over-ripe tomato) "Don't you SPEAK English? A SLIDE!" I had no idea that she was talking about saucers.
6. Be prepared to stand out
You don't have to stray far from the tourist track to be as strange to the locals as a three-headed martian. Even in Tonga where I thought plenty of Kiwis went I got followed down the street by a little boy yelling "hello, palangi!"
7. Never, ever, mime "straw"
Trust me on this one. I am lucky I wasn't arrested.
8. Don't pretend you know more Maori than you do
Maybe I am the Grinch who stole national identity, but I get frustrated when NZers who know very little Maori "teach" poor unsuspecting foreigners, or misusing and misspelling Maori words while showing off. Don’t get me wrong, I think it’s great to spread the use of Te Reo. But, before doing so, it’s important to ensure you get the meaning of the words correct. For example, Kia Ora means more than “hello”. I also get frustrated with Kiwis pretending while travelling that singing waiata is part of our way of life when all they know is "Te Aroha" and the main verse of "Pokarekare ana”. It's great to speak Maori and sing waiata while travelling, just be careful not to put Maoritanga on like a pounamu that gets worn while overseas but discarded into the bottom of a drawer as soon as you get home.
Anyone else got any good tips to add?