I measure success differently depending on which area of my life we're discussing. For many years as a widowed single mother of two, I defined it as keeping a roof over our heads and providing the necessities of life. Happy to say I was able to accomplish that!
Sometimes success can be measured tangibly. In the day job part of my life, I actually have a medal to show that I was pretty darn good at what I did (and still do, for a while longer...gotta pay those bills!).
In my writing life, I always say with a wink and a smile that I want to be Nalini Singh when I "grow up". By which I mean she writes multiple series with highly engrossing plots and intricately designed worlds I want to live in; characters so real and appealing that people discuss them and debate them and demand sequels for them; she's an auto-buy for an enviable swath of readers across the globe, including me...and she's a very lovely person in high demand for workshops, panels and book signings. I <3 Ms. Singh, can you tell?
Oh and she gets to be a fulltime writer! Now THAT is my next desired level of success, which I can cheerfully tell you, is my plan for 2015. Yes, as of March 1st, I plan to take early EARLY retirement from that pesky day job and pursue my dreams 24/7. They're still trying to persuade me to change my mind and continue to do what I do for them. Having tasted the fun and joy of my dream, I know if I can just be fulltime in pursuing it, while I may never reach the heights of a Nalini Singh or a John Scalzi or NameYourFavorite, I WILL be happy and get a lot of books out there. So there'll be an empty office in my building come March 1st.
Now who knows how much tangible "success" I'll find as a fulltime writer, but I guarantee you I'll be doing something I love, keeping a roof over the heads of my two cats and me, and the signs are encouraging that I'm finding my audience of readers, who enjoy the worlds I write in.
As they say, always good to have a really stretch goal out there in front of you - I would LOVE to have one of my books made into a movie. Or a TV movie. Or a miniseries. Someday!