Since I have a very small IQ, it has taken me a long time to understand the 12 Links of Dependent Origination. But I find it one of the most useful teachings for eradicating ignorance, craving, clinging, and nonvirtuous actions that create negative karma.
First some helpful sources:
Knowing And Seeing by Pa-Auk Tawya Sayadaw
The Middle Way by The Dalai Lama
Lamrim Chenmo by Je Tsongkhapa
Some interesting things Je Tsongkhapa said about the links of Sense Contact leading to Feeling and from Feeling leading to Craving and from Craving leading to Grasping:
"Where there is no ignorance, craving does not occur, even if feelings are present."
This means that, when there's Sense Contact, Feeling Arises, but the link of Craving never occurs because there's no Ignorance, so therefore Grasping never occurs either.
"This being the case, contact is the experiencing of the object and feeling is the experiencing of birth or the fruition of karma. Hence, when these two are complete, experience is complete."
So, Sense Contact occurs and Feelings arise. Sense Contact, in this case, is the condition necessary for either negative or positive karma to ripen. This positive or negative karma is now complete. And, if free from Craving, you will suffer less from the arising of negative karma and will not perform more nonvirtuous actions that create further negative karma.
Furthermore, if you think about it, there are two types of suffering that occur when Sense Contact leads to Feelings: the unavoidable suffering from negative karma blossoming and Craving. You can't do much about the negative karma because it has already ripened, but you can let go of Craving to lessen suffering and you can also work to weaken Ignorance at its root by meditating on Impermanence and Emptiness. Also, this suffering that you must now experience because of past nonvirtuous actions can propel you to perform only virtuous actions and do practices that purify negative karma before they ripen through Sense Contact and Feeling.
Points of Attack:
Ignorance, Craving, Grasping, Nonvirtuous Actions
Comments
The way to learn it and understand it is through observation of what goes on inside of you.
Memorizing the links DOES help you identify what your mindfulness observes, but is no substitution for being aware of it.
Do your practice and wait for the dawn.
I saw the 12 links broken down in a way I had not seen before.
Causes - past: Ignorance and Mental Formations
Causes - present: Becoming, Craving, Attachment
Effects - future: Birth, Aging and Death
Effects - present: Consciousness, Mind and Matter*, Six Senses, Contact, Feeling
*Mind and Matter is a translation of 'name and form'