David Brin got his PhD and worked as a physicist before becoming a much-awarded sci-fi writer. He's got some great advice to would-be writers plus some interesting reflections on art vs science as a career:
As a child, despite my talents and background, it was science that struck me as truly grand and romantically noble -- a team effort in which egotism took a second seat to the main goal. The goal of getting around all the pretty lies we tell ourselves. I strove hard to be part of it. But what can you do? Choose your talents? No way. Eventually, as my beloved hobby burgeoned, threatening to take over, I found myself forced to admit that science is hard! I am much better at art -- making up vivid stories -- than I ever was at laboring honestly to discover new truths. At least, that's what civilization seems to be saying. My fellow citizens pay me better to write novels than they ever did to work in a lab.His goal in writing is to induce a state I am familiar with:
Make the book hard to put down -- in order to feed the cat, go to work, go to bed. Your aim is to make the reader appear at work or school tomorrow disheveled and groggy from sleep deprivation, with all of their loved ones angry over book-induced neglect! If you induce this condition in your customers, they will buy your next book. That is the sadomasochistic truth.