Certainly, traing is an unpreddicable job. However, you can use your knowledge and skill to predict the trend of the market. So, you can earn profit.
There's so many people says that trading is unpredictable job, and i agree on that. However, ( like you said ) we need to use our knowledge or skill to learn how to handle the risk. Anyways, we need to do some research about the basic in trading before doing that, so didn't loss our money if we have a knowledge about trading.