Walk by tvor
I love to walk in London. I keep my maps handy but i like to wander the streets and duck down side streets and alleys to discover interesting courtyards and buildings. What some people have been known to do is hop on a bus and stay on for, say 20 minutes then get off and explore that area. I'm not sure i would unless i knew i was still in a fairly touristy or safe area of the city. Even in the central London area though, there are hidden spots to find.Two memories come to mind. Taking a day and walking around the City of London starting at Liverpool street station, discovering old Wren churches and ruins, courtyards and gardens where you would least expect them. There are lots of places to stop for a rest, pubs and coffee shops.
The other was a walk from Victoria Station to the Tate Britain when i got a little lost in the quiet streets of Pimlico, streets lined in white rows of Georgian terraces and little crumbling churchyards. Marvellous!