After learning the first, it is important to learn the second else you will be a trader with a strategy that should work, but no profit to show for it. When you hear of traders who were successfully able flip small account sizes to big ones in a short time, it is not just because of their strategy alone, it is also due to understanding of how to maximize profits and minimize loss.
Maximizing profits is one thing I wanted to learn in trading. After got some profits from trading I have alwasy a tendency to cashout sometimes rather than invest or reroll it as capital on trading again since Ive got plenty of experience losing those profits than cashing them out instead.