I thought of how often the act of writing even the simplest document — a letter, for instance — had clarified my half-formed ideas. Writing and think… - William Zinsser

A writer will do anything to avoid the act of writing.

Soon after you confront the matter of preserving your identity, another question will occur to you: “Who am I writing for?” It’s a fundamental question, and it has a fundamental answer: You are writing for yourself. Don’t try to visualize the great mass audience. There is no such audience — every reader is a different person. Don’t try to guess what sort of thing editors want to publish or what you think the country is in a mood to read. Editors and readers don’t know what they want to read until they read it. Besides, they’re always looking for something new. Don’t worry about whether the reader will “get it” if you indulge a sudden impulse for humor. If it amuses you in the act of writing, put it in. (It can always be taken out, but only you can put it in.) You are writing primarily to please yourself, and if you go about it with enjoyment you will also entertain the readers who are worth writing for. If you lose the dullards back in the dust, you don’t want them anyway.

Decide what you want to do. Then decide to do it. Then do it.