you need to be able to be observant in order to write, just like you need to hear to make music and see in order to draw
only with writing its a lot less straightforward, nevertheless you need to be able to pick up on all the little things going on in any given situation, all the disparate narratives and motifs, all the little nuances and gestures as well as their origins, once you can do that you need to learn to prioritize
style should not be focused on, it will lead to shallow writing which gets boring quickly, style should be allowed to develop naturally along with substance, only then may it be the subject of conscious focus
the same goes for the trivial stuff you can get everywhere, puns and jokes, ironies, political opining, philosophical disgressions, these kind of things should be omited insofar as they come directly from -and are expressed through- you as an author imo