(Correction) Of course Swiss follow the type of their language. Germans are nice, I like them. French are strange. Always. Italians have that food complex.
Don't be a knobber. No one likes knobbers. No one cares how many countries you've been to, or how long you've been travelling. And you're just going to get knocked out of the water by that quiet guy in the corner who's just waiting for you to ask the tired and tested traveller questions that everyone else got bored with years ago. And no, two weeks is not long enough to "do" India.
Don't get complacent. After a week in Rio, several of which were spent on the beach (taking, as advised, the absolute minimum), I was feeling pretty relaxed, but that's just when they strike! I left Tatiane on the beach to go and get my book. While at the hostel I decided to pick up my mp3 player and some water too. Little did I know that a crime wave was about to hit Rio! I returned to the beach. It took me a while to notice that something was missing. Tatiane was still there, as was the sarong that she was lying on. But my nearly empty bottle of suncream! Where was it? Gone! The swine! I bought some more and kept a careful eye on that, and my mp3 player.
Don't (necessarily) trust the locals. Arriving at my latest port of call, I asked the guy sitting next to me about getting the ferry to my next port of call, Ilha Grande. He told me I would have to get another bus for about 4 hours and then change again. I wondered how the hell the Lying Planet could have got it so wrong. It hadn't, he had confused islands.
Buy stuff. Most of my regrets of this trip arise from not buying things. From the freakiest winking Jesus pictures in Ipiales (if you go there, please buy me one) and the second armadillo that was all of £5 to the stolen pair of classic Ray Bans, the only sunglasses I have ever liked, I wish I'd bought them all.
If the weather seems consistently bad try getting up earlier. It may be really beautiful, intensely sunny beach weather in the mornings and then always get cloudy around 1pm, just as you're getting up. (See Rio)
Don't show me your photo milliseconds after you've taken it. I know what it looks like, I can still see it, right in front of me. And I don't care how good your camera is on paper or what genius artistic skill you might have, that 3" LCD screen really can't add anything to the incredible panorama before me.