Get the Kinks' "Waterloo Sunset" queued up while you're on wifi and then walk across the south side of the bridge (side closer to Westminster, Big Ben, the London Eye) at sunset. Perfect.
Waterloo Bridge is a road and foot traffic bridge crossing the River Thames in London, England. The name of the bridge is in memory of the British victory at the Battle of Waterloo in 1815.
Walk around the bridge for picturesque views of Westminster and also follow walk all the till Tower of London on one side and Westminster on other side