SNARKY RESPONSE: Okay, first, Fortune Cookie Guru, you no longer "foretell" anything, instead offering only platitudes, and now you're pandering. Someone, pass me another cookie, at least I can get my sugar fix.
No one believes that one, but I truly believe that you can be successful in anything you pursue with dedication and determination. Granted a measure of "realistic expectation" must be dumped into the mix, but you can't get there from here without hard work. This applies to all facets of your life, but here I'm talking about writing.
What is success anyway? Is it a measurable point in time or checkbook balance? To be successful, you have to determine first what it is, and then what is involved in getting there.
Does being a successful writer mean being on the New York Best-Seller List? Then, more than likely, you need to chart a course for one of the Big Publishers and build your platform to attract their attention. Very few folks get to the NYBSL without that kind of support.
Does being a successful writer mean being published, period? Then, determine what medium is best suited to your type of writing. Self-publishing doesn't carry the stigma it once did, but it doesn't serve the best interests of every writer. Small presses are carrying a lot of water now and could be just the team to take you over the goal line. ePublishing offers versatility and relevance in an electronic age, but is it your final destination or a stepping stone?
All of these venues are valid "end goals" and I encourage you to investigate them all as you plot your course.
For me, the goal is to see my story in print, be it on paper or electronic, and to be judged a good enough writer to be paid for it. Crass, yes, but think about it. If you've spent days/weeks/months/YEARS working on something, investing all that time and effort, you can't be blamed for expecting some recognition. And what better recognition than to have someone exchange their hard-earned money for it. It's not crass, it's about a craftsman being recognized for his trade. And you, my dear writer, are a craftsman, be it prose or poetry, fiction or non, long or short.
Additionally, I would add that any goal you set for yourself (1) is not set in stone--you can change it at any point, it's YOUR goal after all; and (2) is a moving target in that the outside influences on attainment should be factored and adjusted accordingly. Regularly review your goals, check your target for validity, and then be flexible enough to adjust as required.
Finally, "they" say, "Success is a journey, not a destination." (I can't find a definitive citation, but it's bandied about regularly) While it may sound to the snarky like a cop-out, it's a valid point. Even if we don't attain that grand goal, the fact that we continually strive to attain it makes us different from those who don't even try.
That, my dears, is worth celebrating as much as the rest!
So, how do you measure success?