The Ideal App Development Process is the complete cycle that you need to follow in order to get success with your App.  

Idea Validation The most important thing before building an app is to validate your idea to see if it is actually workable, marketable & if people are actually in the need of something like this.  

Before you go ahead & hire a team & starting paying them to do your market research. Carry out a survey. Send out a questionnaire to your people in your family, in your social network get them filled that whether this problem you want to solve is a valid problem.  

Does your audience need these products or services? What are they willing to pay for it? How much they are willing to engage with such an idea/services?  

This is the first & most important step before you incur any cost before you pay anyone before you involve anyone. Just know your idea is validated. It is an actual need of the people.