Trading is a very high intense play in live markets which might be equity, commodity or currency. When we refer to trading, here we are referring to trading intraday in the above asset classes. A person can trade the US markets in S&P futures, QQQ futures, Gold futures, Silver futures, Crude futures, Currency futures, Indian Equity futures, Nifty and Sensex futures. Options can be also traded. The foremost important thing one has to take care is that S/he has to believe in the system of trading one is doing. One should be confident on his style and system of rules of trading. It cannot be that one day you follow x system and other day y system. You need to have back tested your system which should suit your temperament. If your trading style does not suit your psyche then chances are that you may lose in trading.
I would even suggest that one should start trading in a paper trading manner and if you can get a trading coach to help you overcome your fear and greed, then it is all the more better.