A good piece of advice, however for me, i think to be able to become a professional trader you need to undergo circumstances where you would face some problems in trading so that you can have a good experienced, also if you had fail in your first attempt, it can be your motivation not to fail again, perhaps you would learn from what you have done.
More experience and more knowledge will have gotten by the traders to learn from their past experiences. This is the main key that has been doing by so many pro traders. Loss is just a common thing for them all.
People needs knowledge and they can get from doing it.