Oh lord, My response will be the same as it always is.
Build A application you need, or someone else needs, Make the application something that will help you and help ppl you know, test it, usually if a application makes your life easier, it will make others, this concept is used by inventors every day. This is really the best way to innovate, or take a good idea, and make it better, see if this solution best serves you and ppl you know, again if it does, it was worth making