My first post here, although I've been reading for a few weeks this forum.
I am still trading on a demo so I'm still discovering a lot of things about forex but I will talk about what I know : gambling.
I have been a successful slot machine player making good extra money to pay my rent, my phone bill and my school as I was in Japan (we don't have the same kind of Casino here in Europe).
For me I would say you need the same skills to be a good slot machine player and a good forex trader :
Money management skills ( I had times where it took me 2 weeks to save up 20man Yen, earning little every day and blow it up in one day by over confidence ), the rules are the same, find a way to maximise your earning chance, to have the most profitable EV, only risk a small percentage of your bankroll everyday. (usually a fixed amount in casino as there is no leverage).
In slots machine you are looking for the loose ones, and you won't find it at first try. When you spot one who might be a loose one you gotta spend some money to try it out and if you were right you will earn money.
In forex you will wait for a buy or sell signal then you have to take a position, it might be negative at the beginning but you have to stay calm if you believe in the reason that made you take your position.
With slot machine you gotta know how to keep your seat long enough to get all the money it has to blow, but also have to know when to quit to keep profits.
With forex you have to keep your position long enough to optimize your earnings as long as it goes up and have to know when to close it.
So for me gambling with slot machine and forex looks the same ! But ...
In Japanese slot machine ( Pachinko ), all data are displayed on the top of the machine : number of turns, jackpot and the earnings curve (which is like a trading curve) for the day, and usually the past 30 days : http://blogimg.goo.ne.jp/user_image/14/27/9ffaf087651b58081160c28046b9fb12.jpg (example of data screen)
Also the casino has to be big enough so there are a lot of winners everyday ... Usually you can't make money in a small casino, the biggest the bigger
So IMHO you need the same kind of skills to be successful at both (money management, diversification ...), except that your broker is not supposed to be making money on you as a casino.
Statistically it's the same, 95% of forex traders don't make money, I guess 99% slot machine players don't make money.
Actually for me slot machine is not gambling as forex is not gambling. Poker is not gambling. But buying a lottery ticket or playing roulette is gambling. ( you can't have a positive EV, or at least I don't know how to )