Appsumo's got this website full of stories of how people got their first 3 customers. I think that first step is much harder than going from 3 to a 100.

http://www.howigotmyfirst3customers.com/

Create an amazing free trial and give them some real value. They will always want more at the end of it.

some success stories about getting first users - http://vusal.me/handbook/

Find 100 people who want what you're offering enough to pay you. Find a need, then offer a compelling solution.

pay them to pay u