Depending on what you're doing, the right decisions might only be visible in hindsight.

To this point, you might scaffold out a system to get something running and then incrementally / organically improve the system. I regard this as 'getting the system to the point where it can be dogfooded and/or criticized in a helpful way'.

At this point, despite what you might have running, it may be exceedingly clear that you should have used a different strategy. Maybe you like the overall results, but you need things to be implemented in a different way.

For example, I'm a C++ programmer. It's not always obvious at first that you need a specific set of virtual functions to make something work really nicely.

It's impossible to always know these sorts of things in advance.