At the beginning, as soon as you wake up in the morning, generate very strongly the impetus:
Today, I shall keep the two bodhicittas with me.
During the day, maintain them with continuous mindfulness. At the end, when you go to sleep in the evening, examine your thoughts and actions of the day. If there were infringements of bodhicitta, enumerate the instances and acknowledge them, and make a commitment that such will not occur in the future. If there have been no infringements, meditate joyfully and pray that you and all other beings may be able to engage in bodhicitta even more effectively in the future. Practice these two activities regularly. Take the same approach to any infringements or violations of ordination.
From The Great Path of Awakening : An Easily Accessible Introduction for Ordinary People by Jamgon Kongtrul, translated by Ken McLeod. Copyright 1993 by Ken McLeod.
Published by arrangement with Shambhala Publications, Inc., Boston.
This site provides an on-line database of commentaries on the Tibetan Buddhist meditation practices of lojong (Mind Training) and tonglen.