The process that you refer to as "life" is something that can be endlessly improved upon. That is the beauty of it. It does not matter if you live for a thousand years and do everything that you wish to do; something more could be done, something better could be done. This is the way of life. But death is super-efficient; it doesn't need anybody's assistance. Life is happening on so many levels of inefficiency, but have you ever seen death happen inefficiently? When it happens, it is perfect. Perfect and absolute. You do not have to think about death, you do not have to reflect upon death, but mortality -- the limited nature of life -- is something that needs to be reflected upon.
Just watch your breath right now: inhalation, exhalation, inhalation, exhalation. If the next inhalation does not happen, phew. Life is very fragile; don't take it for granted. Just see how fragile it is. You always think somebody else will die, but you will also die. It is just that you won't get to read your obituary. Death is not something that only happens to somebody else -- it will happen to you and me. Death is the one thing that has remained unadulterated. The human mind can corrupt everything else, but death has remained untouched. And death is the only certainty in your life. In your life, you do not know what will happen and what will not happen. Life is constantly uncertain, but death is a 100 percent certainty. Don't have any doubt about it.
Being aware of your mortal nature is extremely important. If you remind yourself every day, twice a day, that you will die, then you will naturally move toward knowing higher dimensions of perception. People think they are immortal, that is why they have time to live foolish lives. But if you know that today could be your last day, would there be time to get angry with anybody? Would there be time to do anything stupid with your life? Only people who believe they are immortal can fight to the death, but those who are constantly aware of their mortal nature do not want to miss a single moment; they will naturally be aware. If you are willing to experiment, just see that you have only two more hours to live. You will become super aware; you will not miss anything.
For many spiritual aspirants, the first part of their training is to sit in the cremation grounds. Gautama the Buddha made this compulsory for his monks. Before he would initiate anyone into monkhood, they would sit in the busiest cremation ground and just watch everybody burning. If you do this, simply look without thinking about it, after some time you will see that it is just yourself. It is your own body. Once you can replace that body with yours and still sit, there is a deep acceptance of death. Once there is a deep acceptance of death, life will happen to you in enormous proportions. But because you have tried to keep death away, life has also stayed away from you. The greatest calamity of the human mind is that it is against death, because the moment you reject death, you also reject life. In your mind, you are trying to keep death out but with it, every other possibility stays out.
It is only when you become aware of death that you want to know what life is about. Only when you start really wondering what life is about does your spiritual process begin. Once you come to terms with death and you are conscious that you will die, you will want to make every moment of your life as beautiful as possible. You will have no time for any kind of nonsense. That is a simple way of being aware.