It is impolite to stare at people in public places; and spitting in the street is considered to be very bad mannered. Also try not to pick your nose in a public place. If your nostrils need de-bugging, use a handkerchief.
Most members of the British public will happily provide you with directions if you approach them politely. Make sure you are familiar with terms like roundabouts, level crossings, traffic lights, zebra crossings, bus lanes, contra flow, and, if using any of the motorways, traffic jams.