Who is going to pay for this?
When you start a product, ideally it is something you want to exist, so the answer to who is going to use it and why is a pretty straight forward one. However, as the user base growth, all kinds of requests pour in. In theory, they sound great, but in practice, how do you justify them?
If you have a feature request, how do you figure if it's truly the right feature, and if so, how much to charge for it, and who to sell it to, if you don't actually know what type of customer is requesting it?
Market research, ask your users, compare the request with what your competition is offering.
That's what I would start with.
First task to implement every possible feature that my competitor has and sell it a slightly lower price, then add more features to get rid of my competitor.
Fair point. I guess do it fast enough, and enough times, and it works out. As long as you are not the one selling everything for zero.