I think the biggest myth with apps today is "if you build it, they will come". I think it was true 10 years ago when the iPhone App Store was getting started, but not today.

The thing is, having a ton of competitors in the space means you will have to work extra hard for your app to be seen and then picked. "Lesson 4: Distribution" in the post is probably the most important thing here. Marketing and SEO are huge in terms of getting people to know about your app.

I have an app of my own in the iOS app store and the times I've had jumps in sales have been tied to either me posting about it somewhere or someone else posting about it on their own. If I don't get the word out, nobody is going to know about my app.

Like the poster, my app is in a crowded space (flash cards), and so a search in the app store doesn't even show my app, at least not until you scroll for a minute or so...