This is what I do mate if they say might be interested,I say can I give you a quote whilst I'm here,if they say yes,I then hand them a leaflet with all my details,so they know who I am,I then ask them to open the gate if need be,then I comment on there nice car on drive or how nice there garden looks,basically get them talking, I then tell tell them I will clean all windows,frames and doors, then give them price,without pausing I say I call on a six weekly basis,I don't call for money but if you in you can pay me if you want,otherwise I will leave an addressed env for you to forward cheque,or I can give you my bank details for toy to pay me on line,is that ok with you ? When they say yes take details,tell them when you will be coming,shake hands, then go and knock next door,and then to the neighbour,I clean next doors windows ,do you require a regular window cleaner ? Then repeat as previous