Normally, retail brokers charge above 5 dollars per 1000 shares and prop shops charge about more than 2 dollars per 1000 shares as the commission rate. According to my many years of experience, these expensive commission rates can make you lose money. The more you trade, the more you lose and more stable you lose(by large number theorem in statistics). It is not an issue that you are intelligent or not. It is simply because the commission is too expensive. The best thing you can do by expensive commission is that you can lose less money but you still lose money. There are two ways to get low commission: register broker/dealer and become exchange members. You need a half million to do this. Secondly, work with a broker that will offer you commission rate less or equal to 0.125 dollar per 1000 shares.