Even though most traders miss the fact that psychology is a gigantic part of trading there is at least a lot of resources out there on the psychology of trading. What is amazing to me is that perhaps the next biggest factor in the succes or failure of most traders is position sizing and even most professional mutual fund managers have no clue about the affects of position size on their portfolio. A quick look around however and it becomes more clear why, because there is no info out there on it. The one place where I have found some good information is Dr. Van K Tharp's Book Trade Your Way to Financial Freedom. I have also put together a video tutorial on the subject which you can find below:

http://www.informedtrades.com/6968-how-position-sizing-separates-winning-traders-losers.html