It's important to think in percentages.

Thinking in terms of “how much have I lost” or “how much have I earned” is only harmful.
On every single trade, think in percentage terms about how much risk you're taking, how you should size your position, and everything else.

As soon as you start thinking in monetary terms, the meaning of that amount for you personally creeps into your thoughts, and these thoughts begin to cause you suffering.

Once you start thinking, “I don’t want to lose this,” “I want more,” or “This is not enough,” your trading becomes very dangerous.‌‌