Find a need and fill it. As a devpreneur, you are addressing some need as a software developer. The needs vary, based on your specific skills and knowledge, but the process is one that provides you with an extensive and valuable skill set. The areas for opportunity have changed over time, moving from PC, to web, to mobile, but there is always some need that needs to be addressed, if you can find it.
“One percent inspiration, 99 percent perspiration.”
— Thomas Edison