Make sure you check out the marketplaces:
Portabello Road, known for its specialty antiques and trinkets, is best on Saturdays, and the alternative, "punk"
Camden Town is best on Sundays. Go to the smaller marketplaces, such as
Chapel Market, near the Angel Street area (northeast London), for a more local experience (and affordable fresh fruits and veggies).
Take advantage of the free entrance to the museums; London has an exquisite collection of fine art. The Tate Modern is my personal favorite.
Catch the sunset on the London Eye.
Quick Tips:
Pick up an
"A to Zed" Visitors' Atlas & Guide to help you navigate the city. The pocket-size book has clear maps on each page of the different sections of the city; it was a must-have for me during my stay.
The weekly Time Out magazine is a good source for special events and shows going on each day.
Exchange your money at the postal office for the best exchange rate and no service fee.
Go to the Leicester Square ticket booth for discount theater tickets on the day of the show. While the well-known, large shows never disappoint, the smaller plays are often just as good, and cheaper too.
Watch out for pickpockets when you visit places like Westminster Abbey, where you stand at certain spots for periods of time, too engaged in what you're looking at to notice someone stealing from you (my friend got her wallet stolen that way).
While afternoon tea at the Ritz may seem like the classiest way to do it, there are many more affordable options that offer a comparable experience. The Orangery, right by Kensington Palace, serves a decent afternoon tea.
Best Way To Get Around:
While most prefer the expansive and efficient Underground system, my favorite mode of transport in London will always be the double-decker red buses, which are surprisingly not that hard to figure out, as long as you have a map. Frequent and reliable, the buses are a lot cheaper than trains, and you can get day passes that let you hop on and off as often as you wish. For a tourist, the buses provide a great way to see the city (who wants to go so deep underground when there is so much to see above ground?)--I once spent a day randomly getting on and off passing buses without knowing where they went, just to see different, yet-to-be-explored parts of the city. Also, the buses run all night long, unlike the trains, so they are convenient for those who enjoy the nightlife scene. As a long-time London icon, riding the buses is an experience you really can't leave London without!