To find a viable business idea, one needs to delve into one domain of life. Over time, deficiencies in the current status quo becomes visible and opportunities to offer a drastically better solution presents itself. If it does not happen, one needs to seek into a different domain. There is a great essay by YCombinator co-founder Paul Graham on this very topic. However, I combine my observation from his essay, personal opinions, and a wholesome amount of information I gained as a listener of the podcast series Masters of Scale. You will find a bunch of references to the podcast episodes below.
To create a rapidly scalable tech startup business that creates a Blue Ocean of undiscovered demand, one needs to generate one idea, implement, test it, and continually improve. This sounds familiar to the Lean Startup concept. But how does one generate an idea in the first place? Ideas come from life. So if you are looking around what social groups you mix with, you can find problems worth solving. Nick Woodman came up with the idea of GoPro when he faced issues capturing high quality action videos while surfing. So the fact that he was a surfer, gave birth to the idea of his product and the company. The popular social media aggregator site, Walls.io gained momentum as the founder was involved in BarCamp. So these two examples show, you can gain ideas from interaction with people in a domain. However, this is not the only pattern to generate ideas successfully.
Mark Zuckerberg was already a netizen before he started social networking site Facebook. Even prior to that he developed a music matching program. He experimented and built tools. For starters, being skilled means you can build stuff for others while you get money for your skill. That is the traditional consultancy job. That was how Zuckerberg got commissioned by fellow Harvard entrepreneurs to build A social networking site which became The social networking site. Also to build out the product from an idea takes strong technical and engineering skills at least for the first phase until one is able to secure enough funds to hire an employee. So having a consultancy business helps build those muscles initially. But building a consultancy business with a keen eye on solving the right problem can reveal even bigger opportunities than the immediate project at hand.
Finally, there is Daniel Ek, who built a successful web development consultancy business when he was a teenager which started as he built websites for others for money in an era when building a website was a non trivial coding work. But that is not what he got his idea of Spotify. It was instead from his personal observation that people downloaded pirated music and record companies were losing the fight. He was living in the domain of music and that is what sparked his entrepreneurial brain.
That is the summary. For starters, building a consultancy hustle can help survive the short term and create avenues to your long term aspiration. Just do not be satisfied with the status quo!