Two schools of thought.
1. Make something. Tell the world about it through marketing.
2. Make something so good the world can't help but to find out about it.
There is no right or wrong answer here but it does draw out the question, is your product/music/project so good that your customers tell all their friends?
If you have trouble getting 100 people to buy your product (not including your friends and family), you really should consider if people want it at all. What about it doesn't make sense to a customer or fan?
I think you should start with option 2, then graduate to option 1.
Option 1 usually costs a lot of money and if you don't have something people actually want, you will just waste a TON of marketing money.
And if you have great word of mouth attention, you can safely spend money marketing to new fans.
GO. Make 100 true fans. If you do it right, that will turn into 500.