The problem with this thread is that the people who need such training are the least likely to actually do it.
I think it's a cool idea to trade in computer games. Many players really make it feel real when they bargain in RPGs and the likes, and immerse into these games far enough to make the market as real as any other.
But I must admit I never did that, just kept an eye on someone who did Diablo 2 trading. He owned the place every time lol, must be in the top 0.1% of rich players easily. It was nothing more than rapid trading on fuzzy statistics at maximum profit. Sometimes re-started from zero, just to leave 90% of players behind after a single day. Getting Enigma before sleeping the first time, to give a hint of the insanity for the Diablo-knowing among you.
Skill and knowledge are everything on high-profit markets, that's the lesson I took from that. (The other one is: one can waste too much time on a single computer game.)