It would be great to hear more about what you are proposing to sell. Are you planning to sell direct to consumers or are you thinking of approaching businesses?
As Andrew has said, defining your ideal customer is the right first step. Once you know what they look like (specific demographics) you can learn more about where you can find them. For example: a business I currently work with sells golf related products. They have fleshed out a marketing and sales strategy that will see them advertise in NZ Golfing Magazine, engage directly with local golf clubs, connect with Golfing Fans on FB and instagram and setup their own Facebook profile.
Also, as Andrew says, make sure you ask for referrals from your current fanbase!