Comment by bumper_crop

Step 1: have a lot of friends. You can usually spend a little politcal capital to get your first few users/customers by talking to them directly. For products that are targeted towards businesses, you'll need to call up your buddies from previous jobs and talk to them about it. After that, you'll probably need to hire a BDR or an AE to start looking for the next few. For B2C, I am not familiar.