Profitable veterans, what's your secret?

Do you follow a simple system or a complex system?

Did you make that system up all by yourself or following your mentor?

Do you think a simple system can make you a millionaire?

It would be really nice if only the ones who are very much experienced in the markets would comment and nobody else.

Both, I don't use a single system. Simple or complex is in the eye of the beholder; what I consider simple from years of auction experience might blow someone's mind (trust me, there's A LOT of people here that think I'm out of my mind), and what they consider simple, say I don't know, something based on Calculus math, might be complex for me.