1. Buy a London A-Z or go to an Internet café and look up your destination on streetmap.co.uk. London is BIG.
2. Ask for "where Lion King is playing" not the XYZ Theatre. Central London is full of theatres, and Londoners don't know all their names.
3. Dress appropriately to blend in. London's a working city, so that means soberly - no shorts, baseball caps, or matching safari outfits.
4. Avoid faux Irish pubs and hunt down a real traditional pub, like the Lemon Tree in Covent Garden and the Red Lion in Crown Passage between Pall Mall and King Street in Central London.
5. On the tube (that's the metro or underground rail system), obey signs on escalators (moving staircases) telling you to "stand on the right". The left "lane" is for people on the move.
6. Get off the tourist trail, away from the tacky, downmarket, overpriced food outlets (tepid pizza, greasy chicken). Turn down a side street and look for a little café.
7. Avoid souvenir shops which have been selling the same policeman dolls for 40 years - unless it's raining and you need an umbrella. Who cares if it says "I HEART LONDON"?
8. The best way to see London is from the top of a double decker. The topless tour buses will point out the sights for you, or you can just get on a double-decker bus and go upstairs. On a short trip you shouldn't get too lost!
9. River trips are also good. They'll give you useful information among the corny jokes.
10. That bridge with the towers is Tower Bridge, not London Bridge. The original London Bridge was built by the Romans, but the present one is less than 50 years old and not much to look at.
11. Enjoy! Londoners are friendly, and it's one of the most diverse cities in the world. Whether you want a steak and chips in Garfunkels or a Lebanese feast in Soho, there's a restaurant for you.