I think people worry too much and psyche themselves out. Writing something that is going to be successful does require that balance, but that is also a balance that we develop a sense for over time. It is also a balance that changes per genre. For example, from what little I’ve read of romance novel, they seem lighter on the details. While in fantasy, my preferred genre, the details are much thicker.

Simply reading other people’s stuff that we like is a good indicator of that balance.

I liked many of the classics, for example. Some of them though were a little thick and hard to read. I pick out those qualities that good literature has and try to incorporate those elements into my book without taking away from the story or putting it on hold.