This, I feel, is a missing critical step. To create something which can stand on its own, and is actually useful, is much harder especially when you have been working for a company for sometime, where a lot of things that you do don't actually matter (not because you are bad, it is just the nature of companies).
A lot of startup reading material talks about immediately charging for your product and while I agree charging is the only proof of a viable business, it is in my opinion step number 2.
Step 1 is building something which people use repeatedly and this product instinct is almost like a muscle that needs to be trained.
Once you create something which gets used a 1000 times (either by 1000 different people or a smaller number of people using it multiple times), you get a taste for it and almost a subconscious feel for what works and what won't.