When it comes to the application marketplace, everyone and their mother is trying to get an application that is going to generate a massive profit without much overhead. While this sounds like a lucrative market, the truth is, it depends on a lot more than just iOS/Android development. Sure, iOS/Android development is very critical because it's what ensures your application on a one-on-one basis is successful, but there is a lot to be concerned about when it comes to application aside from the integrity of your iOS/Android development team.
Don't Overlook Marketing
If you're overly focused on your iOS/Android development team, you're going to overlook the fact that you need proper marketing. Marketing is what ensures people hear about your product. Without it, you'll never have the opportunity to actually get engaged and get people to see all of your hard work. Aside from that, but this is what gets people to listen. If you have an awesome product, you need sales and marketing people to pitch it. Ensure they work with your iOS/Android development team to have an inside and outside understanding of the product. Working in conjunction with an iOS/Android development unit is vital, and this doesn't just include marketing departments, either.
Make Sure It's Proprietary
Without something being proprietary, you're never going to have long-term success. You could have the best iOS/Android development professionals on the planet, but if you cannot prevent other people from copying your idea, then you're never going to have success in any marketplace. Some applications will survive longer than others if the concept has been poached, but you have to be absolutely confident in yourself and your abilities, because if not, you're going to learn very quickly that iOS/Android development alone won't save you from long-term disaster in terms of your application.