As a fellow writer of fiction (The Dread Space Pirate Richard, a sci-fi comedy adventure faerie tale for adults) I was also encouraged to learn that this was another case of an "overnight success" that was years in the making. In an interview with Weir he said that before he started posting his orig blog serialization of The Martian, he already had been writing publically for 10 years and had built up a fanbase of about 1500 subscribers or regular visitors to his blog. So, he had had a big channel of eyeballs ready to go on day one. Even then the serialization didn't explode over night, was a slow grow thing. But a good case can be made that he might never have reached the necessary critical mass of attention for The Martian if he didn't start with that built-in fan channel. Or, it probably would have taken much longer.
Note to self: "I have N years to go. I have N years to go..."