Be aware of your heart when emotions arise. When negative emotions arise, immediately notice the mind. You have to be aware so you can control your emotions. You have to be aware of it so you can get rid of it before it grows and fluctuates.
Don't let your emotions sway you. If you are angry, notice the angry heart, and if you are distressed, notice the distressed heart. If you are anxious, notice the anxious mind. Awareness does not indulge in any emotion. The moment you notice a negative emotion, you can get out of it right away.
Awareness of the mind is the guardian deity that guards the mind.