Many good points brought up here, ill just add to it what I think is the key to profitable trading, in a simple word, to be profitable your overall profit needs to beat your overall loss, therefore you need to contain bad trades to their minimum and ...

The 3 Elements of a Successful Trader

higher than norm spread usually indicates lower liquidity, if spread is an important factor to your trading system, it may be wise to select an ecn broker, spread is generally very low with true ecn brokers, problem is if you are a low volume ...

OANDA Discussion