Walk from east to west, from sunrise to sunset. The rules of the east-west walk:

  1. Find an appropriate location to the east of the city.
  2. Begin walking westward at sunrise.
  3. With reference to the standard Geographers' A-Z, keep within the bounds of one row of the map.
  4. Break for refreshments whenever necessary. Listen to your body.
  5. Stop walking at sunset.

(Simon Pope - London Walking)