I used to pad out my hours as much as possible. Lets just say I was economical with the actual time i spent on the doors. One pioneer who i know is no longer a JW showed me how to rip thru territory as fast as possible. Firstly knock once and as quickly and as lightly as possible. Give the householder maybe 20-30 seconds to answer the door then move to the next one. If someone does answer, say you want to talk to them about the bible, they soon shut the door pretty quickly i most cases.
My favourite tip was to find somewhere where no one was home and just stand on the door step for as long as possible.