If you find you need directions a cab driver or a newspaper vendor will be a good source for directions. If you are in a busy shopping area, you may find a policeman that will be able to point you in the right direction.
Black cabbies own their own vehicles, never leave garbage or food in their taxis. They take care of their cabs and take pride in the appearance so do not make their working life harder. If your cabbie is sociable, they can be a great source of information. Some black cab drivers will not pick up someone who is extremely drunk, and prefer that you do not smoke in their vehicle.
As of July 1, 2007, you are not allowed to smoke in restaurants, pubs, bars, the tube, and in theaters. You will be issued a 200 pound fine if you violate this law. This also includes enclosed places where people work.
Become familiar with the local Tesco, Sainsbury's, and M & S foods. These are grocery stores and you can purchase inexpensive snacks and lunches to take back to your room. This is a great, and more economic alternative to eating out every night.
If you plan on visiting London in the summer months, you will need to be sure the hotel you choose is equipped with a good air conditioning system. Many hotel rooms do not have sufficient cross ventilation and you may find you room unbearably stuffy and hot. When traveling the Tube, know that the temperature can be up to 10 degrees higher than outside. Wear layers of clothing you can peal off.
Do not try to keep up with the locals when it comes to drinking alcohol. Drinking is a large part of the social culture in London, and British beer is stronger than US varieties. You should also know that the Imperial Pints served by the London pubs are 4 oz larger than the pints served in the US. Three British pints add up to 5 bottles of American beer.
When ordering in a restaurant or pub, you may signal by holding up 2 fingers for 2 pints. Whatever you do, make sure your palm is facing the waitress or bar maid. If the back of your hand is facing them it is the British equivalent to giving someone the finger.
If you come across an unattended bag or parcel, do not touch it. Call 999 the emergency help number, this is also true in any type of emergency where you require assistance. This number will also get you in touch with the police in an emergency, and obtain lifeguard assistance. This number can be accessed from any pay-phone. You may also dial 112 to harmonize with other European areas who use that number. If you dial 911 from a mobile it will be directed to the 999 number. 911 will not work on any pay-phone.
Take care when crossing the street, as cars in London are driven on the left side and Americans have had the phrase "Keep To The Right", burned into their brain for years. It can be a bit confusing to you and London van drivers move quite fast down small side streets. Try to cross the street with a group and not alone.