Any resources for mobile app website design?

I am currently designing a website for my company's app. We are a company that started on the web and we are making our first foray into mobile with this upcoming release.

The problem is, I can't find any articles written about how to best design sites to promote an app. I've looked through the list of top paid apps and investigated their sites and there is a lot of design variation. This suggests to me that there is a lot of room for improving on first attempts.

Are there any useful guides or empirical evidence (I'm thinking A/B and multivariate tests) that suggest what needs to be on the page?

I understand of course that each app is different and will require some customization, but as someone coming to this without experience, I'm lost as to site features. Should we include Facebook share buttons? Are longer or shorter pages better? Does motion (video or otherwise) help sell apps or does it distract visitors? How much of the page should consist of sales points vs images? I guess what I had hoped for was a lengthy Smashing Magazine article about the topic, but can't find anything!