Your site needs to have a strong benefit statement. I need to find out in two seconds whether it is worth me reading more. Your primary message needs to be well above the fold and needs to solve some pain point. Without that, any visits you get to your site are somewhat wasted.

Next, you need to think about how to get your target customers to visit the site. Who is your target market and where do they gather? Advertising on Facebook can be fairly well targeted so that you're not throwing away money advertising to people that aren't in your target market.

Finding people that are social 'kingpins' and getting them to become advocates is another method. Who are the bloggers that cover your space? Can they be contacted to tweet or blog about it? Can you develop a referral system or offer the app for free/reduced price in exchange for the referrals. Perhaps Klout.com can be used to identify some of your targets, or, technorati, etc.

J Conrad Levinson wrote some good books on Guerilla Marketing that talk about leveraging this, cross-promotions, etc.

Getting Press Releases accepted by the sites/magazines/periodicals that cover your market is another way. A well written Press Release directed to the right person can sometimes get you noticed.

Social buttons, Facebook Page, Twitter account - all generate buzz and make it very easy for someone to like/share the page. Include referral codes/bonuses so that your client become your best salespeople.

Your sales message needs to do two things. It needs to convey your Unique Selling Proposition (Rosser Reeves, from the 1960's) very quickly, and, tell me what pain you're going to remove. I need to have that 'aha' when I read your site that says, yes, I have experienced that, I hate that, this site solves that problem, let me try it out.

You also have to overcome the 'hot doorknob' syndrome. Someone passionate about the product has to get out there and knock on doors and recruit clients. Since you have the passion behind the project, when you're selling that to someone, that passion will infect them. People that see how excited you are about having solved their problem, will become advocates.

Network, network, network. You know people, they know people, surely someone that you know, knows someone that might use your product.

Get the product noticed. While writing X, we discovered Y was a problem with performance. We documented Z which fixed a problem with multithreaded quantum mechanics. Those stories bring readers, those readers look at what you're doing that caused you to discover that, they recommend what you're doing. Carsabi.com comes to mind regarding Solr - they solved a unique problem, documented that and I would bet probably got a lot of people to recognize their site from the blog post.

Almost any sales book will talk about what it tells to market. Service America is a pretty good book. Tom Hopkins, How to Master the Art of Selling. There are a few other good books, but, almost every sales book has the same message - solve someones pain.

Follow up. Both Twilio and Tropo do very well with this. Recently I had a situation I needed to fix, I set up demo accounts with both Twilio and Tropo. In five minutes, I had a simple script working with Twilio that took about 20 minutes with Tropo to get the same functionality. Tropo's documentation didn't make it extremely clear and I never did find a complete example without having to use urllib to get an auth key to talk with their service. However, that aside, both have sent follow up emails (automated I'm sure) that checked on progress, asked if I had questions, offered help and suggestions. While Tropo ultimately didn't do what I needed and I used Twilio for this quick project, Tropo's followup email mentioned a potential solution to another project I've been mulling over. Without that followup, I may not have reconsidered Tropo. And I knew about Tropo from superconf.net - they were a sponsor and I used their app to be SMS'ed a URL (ok, not a great use case), but, I did have prior exposure and I knew either could solve the first project.

Thirteen contacts with a person to make a sale and it costs more to get a new client, than to keep an existing client. Almost every sales book in the world will tell you this.

Simply. Build something awesome, spread the word, someone will pick up on it and it'll grow. The speed at which it grows is directly proportional to the number of people you pitch.

Some bookmarks referenced above:

Guerilla Marketing:
* http://gmarketing.com/

Landing Page Design
* http://blog.kissmetrics.com/landing-page-design-infographic/
* http://unbounce.com/101-landing-page-optimization-tips/
* http://bococreative.com/blog/30-tips-for-building-a-successf...
* http://visualwebsiteoptimizer.com/split-testing-blog/landing...
* http://www.formstack.com/the-anatomy-of-a-perfect-landing-pa...