I’m really crunched for time so if this response comes off terse or rude, that’s not my intent… I’m just cutting to the chase.
I’m going to say this first part for the people who come after you. You should understand your buyers and how to market your app BEFORE you ever write the first line of code. Anything else almost guarantees a bad outcome.
But, since you’re already in knee deep, I would suggest you start by building “personas.” In short, a persona is a buyer profile.
For instance, for my security app, one of my personas is “Sally” she’s a middle aged, slightly unhealthy, teacher who fumbles with technology and gets easily panicked.
Another persona for that same app is “Adam”, he’s the head of security and is responsible for security related purchasing decisions and implementation of security products.
Now, as you can imagine, Sally and Adam have completely different perspectives. I have to design and develop for both perspectives. My personas have pictures, names and a 120 word description of what that persona needs.
Ideally you want to have done enough research upfront so that writing these personas is easy but, again, you’re already in knee deep so you have to write the persona now which means you still have to do some market research. Getting the persona wrong means your marketing will be wasted effort.
Once you have done your research, you should have 3 personas written. One for your early adopters (those people who can’t wait for your app), the main stream user and the laggard (the people who have Instacart on their phones because it seems like a good idea but will probably never use it or use it once a year).
Now that you have the personas, take the early adopter persona and figure out which editors at which magazines write articles to those people and reach out to them. There may be dozens of those editors or just two. You’ll need a complete story to tell them. Explain who your market is (their audience) and why and what makes it a compelling story for them to write. They may want to interview actual users that fit that persona.
That should get you started.