One perspective I would add is that today, users are being bombarded by an ever-increasing number of products and services to try, especially here in SF!
Investors are eager to know how are you going to grab their attention, and integrate your offering into their daily workflow? This question can be answered many different ways, you can do what AirBnB or Stripe did and aggressively reach out to users by knocking on doors, installing apps directly on their laptop. You can go the marketing route and aim to be in constant contact or create a billboard effect like Lyft's mustaches. But above all, they want to see that you have a well-thought out strategy for doing so.
There are a number of ways to get new users. In my opinion the fastest way to create a buzz is by promoting your start-up on social media platforms, which generate huge traffic on a daily basis. Some of the answers previously mentioned cover majority of the strategies. However, the key is to find ways which are engaging and interactive with your potential target market on social media.
This is one of those questions along the lines of how long is a piece of string. You are creating a consumer product, but however amazing it is, the market for the product will not be every consumer in the world. So by default there are segments of the market that may be interested in purchasing your product.
There are a couple of points made by others I'd like to reinforce:
Given you are creating a B2C I'd really hope you are having conversations with actual potential customers, testing an MVP on them, exploring and refining against their feedback. By the sounds of your question you are going it alone, it would be highly advantageous for you to have someone with sales and marketing skills in your space/vertical/market onboard.
Someone below makes the point that investors will want to see you exhibit a clear understanding of your market, and what that market wants. Armed with that knowledge you should be able to start compiling a plan for entry into the market, and growing sales.
I can assure you the mousetrap theory does not work. Even with all the knowledge you gain from my points above, you are unlikely to have the budget to go all out on sales and marketing, so you will need to be guerilla. You need to be inventive, and brave. I am presuming of course you can't afford to buy Super Bowl tv ads, Richard Branson's Virgin airlines was in the same position a few years ago, so they got inventive: