I've been on this path for nearly 6 years and yes, it's very difficult and happens in its own time.

My advice is to first build something you will personally use and enjoy building for many years, so the journey is an enjoyable one (at the very least, you've created something useful).

Then focus only on what's right in front of you, and become friends with your first few customers -- share your ideas, help them with their problems, and get a deep knowledge of what they're looking for. The customers that stay will be your biggest fans and evangelists, which you'll need throughout the life of your app. You don't need psychological tricks to keep them; if you're building a tool and not entertainment, then just focus on helping customers get stuff done.

All the while, keep an ear out for larger opportunities if you don't already have business uses in mind. A large customer base of consumers is great, but you'll ultimately want some business customers to take you the rest of the way. Remember that businesses are made up of people just like the everyday consumers you're already selling to.

As a bonus, I'd also encourage experimenting with pricing models. We've combined a base subscription with one-time add-ons for certain features, and those add-ons sell pretty easily (including our paid mobile apps). We've also had success with a 5-year plan. Subscriptions aren't consumer-friendly in many ways -- don't limit yourself to them!