Start a conversation with everyone who joins your list. Everybody.
Open your email app and write an email to the last person who signed up. Ask them questions, see if they enjoyed using your free app. Do this for everyone.
Another thing you can do is create an automatic campaign that goes out as soon as someone subscribes. It’s sometimes called a “drip campaign”. Invite your subscribers to ask questions and offer their opinion about your free app.
Soon, you’ll be having a ton of conversations with your audience, and you’ll start to spot patterns.
What’s that one thing everyone asks about in the app? What’s that thing that your users are always trying to accomplish? What are the really serious users trying to do?
Identify a common goal that lots of your users are trying to reach. Maybe they’re trying to save some time, maybe they wish that your camera app could record in slow motion.
Guess what, this is what your audience cares about. Solve one of these problems. They already care about this problem, solve it for them and build the “no-brainer” solution for them.
If you solve their problem, they will care about your app and your launch, and they will buy.