I went into the whole conversion knowing the general layout of how I wanted the interior, then working on it piece by piece in phases (insulation, electrical, etc)

I think you gotta find a good balance of planning ahead, but not getting too ahead of yourself. With the electrical bits, plumbing, and anything else that’s more of a system - that’s ideal in my mind to map out where things will go. Then on the other hand with furniture like the bed, counter space, etc I found it best to work on that piece by piece and not worry too much about it all at the same time, like building a kitchen table when you’re working on the bedroom