Just as with any job, I've started at the bottom and worked up. I had my first publications in 2008. I've published more each year, at higher caliber markets. I have an agent. But there's one thing I've learned as I've gone along--there's no absolute high point where you stop and stay. Every story, every novel, presents new challenges. The rollercoaster metaphor is used an awful lot, but it doesn't quite do a writing career justice, not unless this rollercoaster is on a flat, rickety track that drags on for weeks or months of nothingness, then out of no where can drop like Niagara Falls or zoom as high as Everest.
Because if there's anything you can depends on in this publication game, it's waiting. Lots of waiting.
You write and do what you can, and after that, the story is beyond your control. It's up to the slush readers, interns, editors, and agents--and the readers, after publication.
I have particular long-term goals in mind as I rumble along on this rickety track. Within five years, I'd like to have a story or novel make the shortlist for a Hugo or Nebula. I'd also like to have a poem up for the Rhysling Award.
These are shiny possibilities off on the horizon. I can't control if I get them; in the meantime, I keep writing. I keep submitting. I keep going down the track.