First do the preliminary practice of guru YOGA as it was described above. Then you should meditate on love and compassion. They form the basis for taking and sending. start by imagining that your own mother is present in front of you. Think about her carefully with such reflections on compassion as these:

This person, my mother, has looked after me with great effort right from the moment I was conceived in her womb. Because she endured all the hardships of illness, cold, hunger, and others, because she gave me food and clothing and wiped away my filth, and because she taught me what is good and steered me away from evil, I met the teachings of Buddha and am now practicing the dharma. What tremendous kindness! Not only in this life but in an infinite series of lives she has done exactly the same thing. While she has worked for my welfare, she herself wanders in samsara and experiences many different forms of suffering.

Then, when some real compassion, not just lip service, has been developed and instilled, learn to extend it step by step:

From time without beginning, each sentient being has been a mother to me in just the same way as my present mother. Each and every one has helped me.

With this sort of reflection, first meditate on objects for which it is easy to generate compassion: friends, spouse, relatives, and assistants, those in the lower realms where suffering is intense, the poor and destitute, and those who, though happy in this life, are so evil that they will experience the hell realms as soon as they die. When compassion in these areas has been instilled, meditate on more difficult objects: enemies, people who hurt you, demons, and others. Then meditate on all sentient beings, thinking along these lines:

All these, my parents, not only experience many different kinds of suffering and frustration without intending to, but are also full of potent seeds for future suffering. How pitiable! What's to be done? To return their kindness, the least I can do is to help them by clearing away what hurts them and by making them comfortable and happy.

Train in this way until the feeling of compassion is intolerably intense.

Second,

Train in taking and sending alternately. Put them on the breath

As you think:

All these parents of mine, who are the focus of compassionate hurt directly by suffering and indirectly by the source of suffering, so I shall take on myself all the different kinds of suffering in all my mothers' course of experience and the source of suffering, all disturbing emotions and actions.

meditate that all of this negativity comes to you and foster a strong feeling of joy at the same time. As you think:

Without regret, I send all my virtuous activity and happiness in the past, present, and future, my wealth, and my body to all sentient beings, parents

meditate that each individual receives all this happiness and cultivate a strong feeling of joy in each one's receiving it.

In order to make this imagined exchange clearer, as you breathe in, imagine that black tar collecting all the suffering, obscurations, and evil of all sentient beings enters your own nostrils and is absorbed into your heart. Think that all sentient beings are forever free of misery and evil. As you breathe out, imagine that all your happiness and virtue pour out in the form of rays of moonlight from your nostrils and are absorbed by every sentient being. With great joy, think that all of them immediately attain buddhahood. To train the mind, use this practice of taking and sending with the breath as the actual practice for the period of meditation. Subsequently, always maintain the practice through mindfulness and continue to work with it. Shantideva, who has described this practice extensively, says:

If I don't completely exchange
My happiness for others' sorrow,
Buddhahood will not be realized.
There is no happiness in samsara.

From THE GREAT PATH OF AWAKENING, by Jamgn Kongtrul, translated by Ken McLeod. 1993 by Ken McLeod.
Published by arrangement with Shambhala Publications, Inc., Boston.