1 - First thoroughly vet your idea, talk to your target customer base, ask them if they have a problem that you are solving
2 - Understand this problem throughly, why are they having this problem? what changed that they are having this problem suddenly? Why is your solution better that anything else that is out there? Why would they buy your solution and not some one else's? Is your solution easy to use? Would your target customer base pay for your solution? How much they will pay?
3 - Then quantify that problem, is it big enough, are there many people that have this problem, the more people that have this problem the more money you can men
4 - Then develop an MVP - Minimum Viable Product that solves that core of the problem, then show it to your target customer base, ask them off they like it, they might come back & say - improve this, improve that, listen to that feedback and improve it, make it better, the best, fix all the bugs, make it excellent
5 - Then use these metrics to raise funding or if you have the cash go ahead and develop a solution and start selling
6 - See what is resonating among your customers and come up with that value prop, articulate that value prop through blogs, videos and in marketing material
7 - Keep improving, make your solution into a platform and provide more value, so you can charge more
8 - Build strategic partnerships, so you can sell more, figure out all possible ways to sell more, so you can make more money for yourself, your employees and your investors
9 - A startup is never complete until you sell it to somebody or you quit your job as a CEO, hopefully making a good amount of money for your self. If you are not selling, nor quitting then keep improving, look for the next game changing thing that happens in that area and keep on improving, expand to other markets leveraging the same model, expand internationally, expand to other verticals in the same area etc
Also check out my book Puga Sankara's Supply Chain Blog - that is a must read before spending Hundreds & Thousands of $$$ on your MBA or Masters Degree to get the best ROI or before starting your Entrepreneurial journey.