What made you a successful stock investor?

Experience and reading. Sometimes losing money teaches you alot, I think almost everyone lost money in the market before making money. Put it this way, 7 or 8 years ago I remember thinking how much more I knew about investing then I did in the 90s, and how I understood so much more about it all. Today I look back and realize that when I was thinking about that 7 or 8 years ago, I really knew nothing. You never stop learning.