It's not enough nowadays to create something you want, instead you'll need to focus on what people need. If you find a need for something that isn't available... You should create it. Odds are someone will find it useful as well.
When you focus your energy on building something that you are passionate about it's going to show. Your customers will buy because it's a great application, but also because they believe in what you are trying to achieve. So, continue to focus on making something that people need and find useful.
You may have a need to only want to make money from your application, but if your application can help others achieve a goal and you can make money from it too, you have a gold-mine.
Some more info on your awesome post here. After this sentence, it's just going to be a little bit of jibberish. But you get a general idea. You'll want to blog about stuff to get your customers interested in your application. With leverage existing reliable initiatives before leveraged ideas. Rapidiously develops equity invested expertise rather than enabled channels. Monotonectally intermediate distinctive networks before highly efficient core competencies.