In my own trading career, I'd have to say the hardest thing is dealing with your own emotions and rationalizations.

You really are trading against yourself every time you put on a position.

A system can help, and the discipline to stick with it. But I've blown out a few accounts learning the hard way about second guessing my plan or just trading out of "gut feel" for a situation.

Thanks for your post, it was helpful getting another perspective from a fellow trader.