When I tried offering my first web application in 2001-2002 with a 30 day free trial I has 1,200 trial sign up and 3 conversions. I didn't follow up with those who signed up, I didn't collect phone numbers to make any phone calls, I failed in that partly because I just didn't engage the consumer. I got them in the door but left them hanging to figure things out themselves and sell themselves.
The business was very much customer-service oriented. Every new customer got a phone call to ensure that they were properly set up, give them a 5 minute or so introduction to the product, and personally invite the customer to a weekly live training webinar.
They catered to less computer-savy people mostly, but even the technical folks seemed to appreciate the personal touch.