Hi Keith, and welcome to the madhouse.
Ways to get yourself and your business known are either by door to door knocking, having leaflets produced and distributed, or a combination of both.
Door to door knocking is the fastest way to get customers. When I started up, I was tooled up and ready to go as soon as I found my first customer, and was earning straight away. Others canvass in the evenings (tbh better for finding people in) or weekends and go back and clean. Which way you choose it up to you.
It took me around 6 months to get my first 100 customers, but then I only canvassed during the daytime. If you do evenings you may well achieve this in a shorter timespan.
Realistically, you need to be determined and motivated, but I always try to apply the rule of 4 P's when canvassing. Be Presentable, polite, professional and positive.
It is a numbers game. every door you knock will find you closer to your first (next) customer. Do this for the next 2 years, and you should have a decent customer base.
Just a thought, have you thought about telling your pressure cleaning business customers that you are adding window cleaning as a service?
Best wishes,
John