As further reference to the 37 factors, I have always found the Anapanasati Sutta to be interesting, here the Buddha mentions: http://www.accesstoinsight.org/tipitaka ... .than.html
"Mindfulness of in-&-out breathing, when developed & pursued, is of great fruit, of great benefit. Mindfulness of in-&-out breathing, when developed & pursued, brings the four frames of reference to their culmination. The four frames of reference, when developed & pursued, bring the seven factors for awakening to their culmination. The seven factors for awakening, when developed & pursued, bring clear knowing & release to their culmination."
This has been the mainstay of my practice, I am not sure if it is possible to develop each 37 qualities on its own, as some of them naturally co-arise through practice, for example without the four powers, one cannot refine the skill of meditation.
Moreover, the five faculties and the four right exertions are needed in the course of meditation itself to analyse the four frames of reference.
The seven factors of enlightenment gradually unfold as a result, culminating in the path.
Thannisaro Bhikkhu's book as mentioned by Retro is a good study guide, but reading his book is quite hard as I have *tried* to read his book from back to front a while ago.
Being a lazy person that I am, I am just inclined to sit and do nothing, just watch the breath, feelings, and the mind... as the breath goes in, as the breath goes out
All the best, and I hope this thread stays alive for the benefit of all. It is indeed quite rare to see these 'hardcore' topics being discussed.