Once upon a time (doesn't that just take you right back to childhood stories?) there was a Persian King who wanted to learn the secret of equanimity*.
He instructed his wise men to give him one sentence with which he could always calm down when he got upset; a set of magical words that would help him in any given situation. His wise men ended up asking a mystic to help them out. The mystic pulled a ring off his finger and told them to give it to the king. The magic words were engraved beneath the large gemstone of a ring. In one version of this story, the mystic attached one condition to the use of the ring: the king was only allowed to read the words if he saw no other way out.
The king wore the ring at all times, obeying the condition, without looking at the inscription. The mere knowledge that there was a magic charm to lift him out of any depression was a huge support to him.
He reigned for many years in peace and happiness. But then, things went wrong. His kingdom was attacked, he had to flee, the enemy gave chase, his horse tripped and died, he had to run for his life and found himself on the edge of a cliff.....At that moment, he took the ring off and read the inscription:
"This too will pass".
Back to today.
One thing that is crucial for developing equanimity is a friendly, tolerant attitude towards life, called compassion, that Buddhist virtue, not just for others but especially for yourself.
Staying in the moment with a clear and open mind, being kind to yourself and others: that is equanimity.
* equanimity is a state of psychological stability and composure which is undisturbed by experience of or exposure to emotions, pain, or other phenomena that may cause others to lose the balance of their mind. (source:wikipedia)