A big reason why my interest in window cleaning went from “Hey this could be some good part time money” to “Hey, you can make a good living at this”, is because of Don Marsh and his youtube videos. Topics range from ‘Starting a window cleaning business’ to ‘Techniques of the trade’ to ‘marketing your business’
He has a web site, http://squeegeesbymail.com/e107/news.php
and all his videos are on there. I find that many of his videos answer the common questions that people new to this trade will have. His topics mostly apply to residential.
Here’s a couple of samples: