Do not write about the sins of the Hollywood film industry unless you know this world well. Even so, you must always master the rules of the genre in which you wish to work. Sci fi sells to hard core fans who read little else. You have to know this genre inside out if you expect to write and sell books to the Trekkies. Ditto horror, romance, porn, and a few others.
Writing is very hard work.
Those folks who try it for any length of time understand that fact. Writing good fiction is so damn tough very few people succeed at it. It seems that those people who do it best are thoughtful, careful readers who study successful writers and learn the techniques. Like glassblowing or painting, writing is a craft that can be learned, but it must be practiced diligently and painstakingly. Like every craft or art, good writing requires a spark of originality or all the sweat will have been in vain.