Following is the "summarized" process that you should follow to build any Startup Business:
1. Find the Problem (idea) & think of its Solution (Product). Any innovative idea will work too.
2. Do the Market Research & get Statistics as it will help you to take a decision whether building this startup business is worth or not.
Eg: If you do market research and found that there are already too many competitors present and that the customer bifurcation/segmentation is already at its peak then you must not enter into the market until & unless you have something extraordinary to put in.
3. Build a PoC / Minimum Viable Product (Prototype) and it is advised that at this stage you do not invest a lot of money as it will be a prototype only.
Eg: When AIRBNB was planned, it came out because of a situation where founders were struggling to pay their rents. They offerred mattresses in their apartment to attendees of some conferences. This unknowingly validated a concept that an apartment, or similar real estate can be "shared" to provide places for the people looking for stay or so.
4. Get the Initial Traction from the MVP (Prototype) you have build to validate the market fit. Revise until you get at least 50% market approval.
Eg: If you building an application that will simply track the people or objects through GPS then you need to give it to a couple of people initially so that they can use it and give you the feedback. Based on the feedback you can simply make the changes until you get at least 50% approval.
5. Work on your Product Positioning (Along with PoC / MVP) strategies as you need to know which market (segment) is going to accept your product & will value it.
Eg: One of the great example of an improper product positioning is the Apple's Newton PDA which was build ahead of its time and users were unable to understand that what to do with it. The market was simply not ready for it. This is why you should do some research.
6. Build an excellent Go To Market Strategy to put a footprint of your product because if you fail or lag in building the GTM strategy then its hard to penetrate the market.
Eg: The good example for GTM will be ONE PLUS ONE (the mobile phone company) which made it so desireable that people were psychologically forced to buy it. The company simply penetrated a satured market filled by the giants like APPLE, SAMSUNG, MOTOROLA etc.
7. Get Initial Traction from the market. Revise strategies if necessary. This will help you understand how the market is behaving that will allow you to make improvements in your product and also the initial traction is a proof that your business is investment ready.
8. Approach to Investors but don't rely on them. Investment process takes at least 3-6 months. Investors will take their time and during that time unknown factors can change the deal. Bootstrap yourself until then.
A lot happens and things to be worked before actually executing the idea. Value the Time & the Money and you will get the good returns.