Never get Italian students talking about food. Be careful about using the term "Outer Mongolia" when you might have children in your class who come from that region.
And if you are a larger-than-average woman planning to travel from Britain to teach in China, you might want to consider packing extra supplies of underwear and shoes.
These are just some of the hints and tips on offer from teachers in a new book showcasing the potential pleasures and pitfalls of teaching English as a foreign language around the world.
Lessons in your rucksack, by John Hughes, aims to offer a comprehensive guide for young teachers considering their first teaching trip abroad. It features anecdotes from around 100 experienced travellers, giving an insight into the striking variety of challenges facing the teacher overseas.
One told of arriving at a school in China and finding that all the textbooks were locked in a cupboard, to which teachers were denied access.
Another, teaching in Italy, said: "Never get Italian students on the subject of food! They're so passionate about it they'll come to blows discussing the subject."
One, teaching in London, said: "I asked a class to imagine that they were describing something to someone who came from Outer Mongolia. One of the students put up their hand to say that he did come from Outer Mongolia."
The inventiveness of some teachers is striking. One teacher claimed to have taught the basics of English to locals in a village in Peru using only the lyrics of Pink Floyd tapes he happened to have with him.
Another teacher told of arriving in Poland and using the stubs of his airline tickets to teach students numbers and telling the time.
Contributors were also asked what the new teacher should pack for their first trip abroad. Radios to pick up the BBC World Service were popular, as were Beatles tapes and Marmite. Women travellers to China were advised that clothing in larger sizes was difficult to come by.
Mr Hughes was previewing the book at the annual conference of the International Association of Teachers of English as a Foreign Language in Liverpool this week.
Lessons in your rucksack will be published next month by Modern English Publishing. For more details go to www.modernenglishpublishing.com or contact Marston Book Services on 01235 465537