how to build a customer base

I'm looking for some advice on how to build a customer base quickly. I know that it's important to have an email parsing tool in place, and I've been looking at the options out there, but I'm not sure what to look for in a tool that will help me build my customer base. Do you have any advice?

Customers are the lifeblood of every business, so figuring out who they are is crucial. They are the ones that buy the most of your wares and put the greatest faith in your business to get them where they want to go.

Tell me please, how?