The 'West End' is not an officially defined area of London but I have lived here all my life and would loosely define it as the area between Marylebone Road to the North (Madame Tussauds), Piccadilly at the South (Royal Academy, Green Park), Park Lane to the West (posh hotels and Hyde Park) and Tottenham Court Road to the East (Foyles bookshop and the British Museum). The area covers maybe 3 square miles of the prime tourist territory in London so includes a vast amount of attractions - shopping, eating, museums, art galleries, gardens, churches, theatres...the list is endless. My best advice therefore is to avoid the main thoroughfares as much as possible i.e. Oxford Street and Regent Street for instance and focus on the myriad of side streets. For the most interesting walks around I would try the streets around - Marylebone High Street / Marylebone Lane / Great Titchfield Street / Goodge Street / Berkeley Square / Hanover Square / Curzon Street / Brewer Street / Wardour Street. These streets are best explored during the week when the cafes are open and all the office workers are around.