I've been a tour guide.

The things a guide has to remember are:

1) You are the expert, so the people taking the tour will believe everything you tell them. Everything. If somebody asks you a question and you don't know the answer, make something up.

2) Either find or invent stories about the things between the important stops on the tour. You have to keep talking as you move from Important Thing A to Important Thing B.

3) People love trivia and good stories. If you can point to something and say it's the oldest/biggest/first whatever, do it. If you can alter a common joke or folktale to fit the local scene, do it.