Your not going to get a landing page that's going to work on the first try. also, each marketing channel may need a new page. use something like unbounce or optimizly create basic landing page. find your best 1-3 keywords on google and see if you can get any one to click past the first page. I found a basic landing page template and paid someone on elance to integrate a wufoo form and istock images into it. I ran the unbounce page with a button saying "try it" pointing to the landing page with a wufoo lead form. if people click past it to the lead form you have a basic landing page that works. if not tweek it or start with a new idea. once they click past your landing page tweak the lead form page/minisite to get them to fill out a lead form. then, you have some people to contact you can get some basic feedback of your product. then test against different versions of your landing page etc. Once you have too many people contacting you can look into automating the sign up/onboarding process.
