Performance goals:
They need external validation.
They involve extrinsic motivation (appearances, compliments, recognition).
They become demotivating when you don't achieve them.
They are outside of your control.
Mastery goals:
They focus on learning.
They concentrate on mastering the process.
External validation is irrelevant.
There is an emphasis on the joy of doing the activity itself.
You are more likely to feel good about your own progression regardless of outcomes.
For example, instead of setting a goal of dropping body fat by 8%, I set my goal as mastery practice, executing a well-designed meal plan.