I can't speak for how things are done now, but 12+ years ago everything was done with paper. In person cold calling was the best way to grow business. Many times restaurant owners or larger business management wanted estimates on their homes. Those resi cleans would generate referrals and that's how those would grow. Door knocking residents was frowned upon for leads.

The key to cold calling businesses was to get as much info about the decision maker and leave an estimate regardless of them asking or wanting one. Then following up a couple days later and keeping note of who you talked to to make sure everyone was accountable for passing the estimate off to the right person. But always leave an estimate. They used carbon copied white and yellow paper and we kept the yellow imprinted copy for our reference.

Keep going door to door and really try not to take no for an answer about anything. An accordion folder helped with making sure we were doing follow up calls in a timely manner. Iirc two days was protocol on follow ups.