If I were to take the measure of my success right now, I would be very conflicted. The "ultimate," as in the goal I am actively striving for, would mean that I am able to survive without the day job. So I would not today say that I feel particularly successful. I work.
I have published six books through a major New York house. I don't get to whine. It is a dream come true and I know everyday that I have done something that thousands and thousands of others also dream of achieving, and I cannot dare besmirch that gift by actions or words that seem dissatisfied.
Less than ten years ago, I would have killed for the weekend I just had at DragonCon. I got to talk to likeminded creative types, both published and those still working at it. I got to sit on panels with my peers (squee--I get to say that!) I could name drop some of the biggest names of my industry, as in I had drinks with them, went to dinner with them, hugged them, was teased by them on panels that had audiences hooting with laughter, I had the ear of an editor I have wanted to work with for many years, I had the ear of a couple editors I'd never previously met.
Have I met the goal I set for myself? Maybe not. But damn, I am HAPPY and if that's not a measure of success...I dunno what is.