Being a tour guide is a pretty horrendous business, and not something to voluntarily engage in unless you are financially desperate. This may sound excessively pessimistic, but look at the facts:
Tour guides are considered by all other employees to be a lower form of life. They are routinely ignored, spat at, and otherwise derided - often by members of their own group.
Tour guides say the same things many hundreds of times a day to the same bored-looking people. This may seem obvious to you now, but wait until you've done it for a few days. Or hours.
It is a tour guide's fault if anything at all goes wrong during a tour: a child falls over, it begins to rain, someone receives a parking fine. Anything.
Tour Guides Must Know Everything
From Day One you must attempt to learn everything - from the maximum temperature of a gas-fired kiln to the average number of pots produced by two men working flexible shifts in four calendar months. You must also be aware of obscure monarchs, even more obscure artists and be prepared to answer questions on that statue in the corner of the square hidden by the shrubbery.
Tour Guides Must Make Things Up
Sounds dishonest, but let's face it - the last thing you want if your little girl asks a bizarre question is for the guide to say 'Er, I dunno'. An example:
Small Boy: 'Scuse me - how many tons of clay have been dug up since the beginning of time?
Tour Guide (pretending to do complicated calculations): Well, we can't be sure but we think it's something like 4.5 thousand million metric tons.
Small Boy: Really?!
Tour Guide: Oh yes. Quite definitely, as a matter of fact.
Statues of obscure kings and queens often become Henrys I to VI or Anne Boleyn or Anna of Cleves.
Tour Guides Must Speak Loudly
This is not to prevent people asking you to speak up. They never do. A dozen senior citizens will prefer to wait right until the end of the tour, just before you are due to have a lunch break, and then ask you to repeat to them, individually if possible, every word you've said in the last half hour.
Tour Guides Are Not Entertainers
Your astonishing theatrics are unlikely be entertaining; your gag-cracking at the expense of 19th Century clay merchants at a crucial point in the tour will be met with silence. Just speak up and sound interesting, for pity's sake.
Tour Guides Must Work Out the Nationality of Their Visitors
If they speak the same language you do, that's dandy. Unfortunately, you will find visitors from another country to be somewhere on a sliding scale from total fluency to utter incomprehension. Speak very slowly (assuming the latter), unless they look at you with the 'How dare you patronise me?' glare. And whatever you do, don't attempt to speak in their language if you don't know it, as that just adds insult to injury.
And never confuse Americans with Canadians or Australians with New Zealanders.