The most important thing that any business does is markets its goods and or services. Sadly, it really isn't true that if you invent a better mousetrap that the world will beat a path to your door.
You have to make them aware that you have indeed invented that better mousetrap.
The most effective way of doing this is to use a marketing list. Say, for example, your service will appeal to lawyers: and only lawyers. You thus will want to get in contact with list brokers and get a list of lawyers from them. No point in spending any money on advertising or trying to sell to anyone else, is there?
Or if your product is of wider appeal, you might want some consumer mailing lists.
Whichever it is that you need, worth clicking through any of those links to see what The List Company can do for you: they've got 300 million Americans and more than 14 million businesses on their databases.