Most traders fail not because they lack intelligence, but because they lack having a strong grasp on a system that works. Without clear rules for risk management, position sizing, and emotional discipline, many people end up making impulsive decisions.
Common mistakes include overtrading, chasing price movements, increasing position size after losses, and abandoning a strategy after a short period of frustration. And the biggest mistake of them all - not using a stop loss to prevent big losses.
Developing discipline and learning to follow a structured approach is what separates traders who last from those who eventually quit.