We have to dismantle our ego. Then, surely, the inner peace pour rapidly from the core of the heart. To dismantle the ego, we can follow these things:
1. we have to observe our thoughts first. If we observe them, we surely get that they are the workings of only "ego". Just observe objectively. Neither oppose nor support. Just observe. They are the main cause of spoiling inner peace. If you observe continuously, whenever you will get the time, sooner those thoughts will vanish. It takes some time. But, by continuous practice, we will achieve it.
2. Then, we have to observe our emotions. If we are angry, then, it is only "ego". Our true being does not have those negative or positive emotions. It has only stillness, peace and happiness. So, whenever you face those emotions, just tell to yourself that they are the workings of "ego". So, tell yourself that "I must not respond in that way. " It's not that much easy. But, it is the practice we have to do. By practice, we will get it. Especially, for negative emotions, don't respond.
3. Then, if you find a man behaving with "ego". Just don't react with your ego. Just calm down and say the fact as peacefully as possible. We must know that for somethings, we have to fix, for some other, we have to postpone, for some other, we have to walk away from that place. we must know this thing.
I am putting my thoughts as they are coming to me.

realising the shortness of this life

I realised that I will die tomorrow or after some years but it is certain. This life is shortest. May be, my mother's death may have compelled me to think of death. Even, once I read one of the answers of Swami Vivekananda :"You must think of death for some days. It will surely make you worried and disturbed. Even though, you have to think of it for several days. Then, you will get that you are temporary and your truthful living starts from that day.". May be, it had shown some effect upon my thinking.
Later, I read an interview with Mother Teresa which was given in Times, to the one of the querries, she said : " we are not sure of tomorrow. We may die even in the sleep." All these cumulatively showed effect upon my thinking.
But I am right to think of it. It is not at all pessimistic and waste. It forced me to think of what to do then. I don't know as of now. But, it had started search for the purpose of this human existence in me.