Create a landing page for your product to start collecting user emails. This can be a simple HTML page, a video, or a static page, etc. made with one of the landing page builder tools below.
This landing page is the front page of your website/service. It is supposed to fully illustrate what your MVP does. The UVP, sub-headlines, and content you put on your landing page (great example: http://csspiffle.com) can already tell you if you will have the right solution by the response from your potential customers when they sign up and leave you their emails.
Do not wait till you are done with your product/MVP (Minimum Viable Product) to start collecting early adopters. A lot of startups think that they cannot get customers before they have a product ready. Read the Dropbox story below to see how they got 75,000 customers even before they had a line of code written.
Also, do not make your landing page look too raw and generic. When users see that you didn't put enough effort in building the page, they will feel annoyed and actually feel negatively about it. Make sure whichever tool you use to build your demo page, customize it well so it includes good content like a strong UVP, mockups or screenshots, images, and valuable information that could excite them.
You can use stock images and perhaps some of the platforms' default templates to help you create something beautiful.
Mandatory elements you will need on the demo page:
Case Study: Dropbox had a 3 min screencast on Hacker News that got a lot of feedback. They did a simple landing page with information to collect beta emails. They had a link that said “Google Drive Killer Coming from MIT Startup”, which gave them 12,000 diggs and 75,000 signups…in one day. They also got into Ycombinator with all that interest they generated.
Another AWESOME Case Study:
CSSHat had a really great looking landing page here (CSS Piffle) that promised to help designers solve the problem of having to convert Photoshop images into usable CSS. They tweeted their service, and they got 10,000 potential users within weeks. The landing page was so awesome that even though it's been static and unmanaged for a year now, still many users ask about it.
Dropbox and CSSHat put a concrete idea in their customers' hands, which wasn't the usable product, but it was enough to prove what they're doing is what people want. That said, you can basically create a simple landing page that explains what your solution is, and some basic info on how it works.
You don't need a restaurant to test your food concept. Aspiring chefs have used food trailers as a way to quickly test their product while keeping their risks super low. – Ash Maurya
You can even get Google Adwords or some ads to test to see how attractive your ad is. A blog entry would work too. If a lot of people click on your ad, that immediately shows you the demand for your service.
Case Study: Ash Maurya validated his idea using a blog post named “How I Document My Business Model Hypotheses.”
There are companies that create these demo videos that help potential customers visualize your solution while getting sign-ups for your service.
Don't spend too much effort creating a “demo” page. Ideally, when you are creating your demo page, you should be somehow designing your eventual website's front page. Any effort not put into making the final product is a waste. Making a video is good because you can use it after you launch.
Create a static demo page:
7 good examples of landing pages: http://www.hongkiat.com/blog/coming-soon-page-design-with-examples/
Companies that will make your demo video
Make your own screencast: