yeah trading is unpredictable job if you want to trade first you need to know that which currency is secure and strong and then you should start trading and trading is depend on you if you have good knowledge about trading then you are good trader.
i agree with you , you are right that first you need to know that which currency is good for trading and then you can start trading with that good currency and its true that trading is depend on your skill or luck .
Its unpredictable but if you done your all home work with analysis and research then its also very profitable because its need some time when you want to in and want some good profit