The first objective to attaining success is determining exactly what success means to you. What would it take for you to feel that you are a success? In our society, we often view success as making lots of money, having power/talent/beauty and being recognized for such attributes.
However, success comes in various levels and doesn't always have to mean wealth and fame. Accomplishment of a goal is well worth pursuing. Success can be harvesting vegetables from your first garden or the completion of a manuscript. There is no greater excitement than the "I did it!" moment.
But, the thing is to keep your success in perspective so you will always enjoy the moment and look back on your successes, no matter how small, with pride. It is easy to let success become an enemy because for every rung on the ladder, there is always another rung. Unfortunately, success walks hand-in-hand with failure.
For a writer to make the NYT bestseller list is to be considered a success, more so than other writers. However, unless they make the #1 spot, they are still not tops, and if they do, how long does their book stay there? Long enough? And what about the next book? Success becomes frail quickly, and, sadly enough, it can take its toll on anyone.
You avoid that trap by celebrating your achievements as something that has made you happy, made you feel good about yourself and your capabilities, given you a good memory to cherish and the will to stay on the ladder. Remember, success will only make you feel badly if you expect too much of it, if you start comparing your success to what others have accomplished, and if the worry of failure overshadows all else.
It doesn't matter where you are on the ladder. You can go up and down as much as you want.
The main thing is to enjoy the climb.