How can we become free from irritability?

From: Meenal Manikantan

Though theoritically we know not to hate anybody but only be compassionate, at times our tolerance level drops so low that almost every body we come across irritates us and we get angry. I am able to understand that the cause for the anger is not from outside but with in one self only. However it may be, it is not pleasant to be angry, how to be free of anger and irritation? Please advice.