hmm.
From one meditative perspective, "not being the mind " is predicated on some understanding & experience of the fundamental difference between natural thought and deliberate thought.
Here "not being the mind" simply describes a mind whose primary operating agenda is to be less habitually attachment bound to any phenomena that it encounters.
It's not so much an organic definition as it is a path.
how
This question is good.
Its answer is like looking for the true origin of a stream where every conclusion is preceded by the next until we see that its water itself that defines it. The stream is just a momentary expression of water's movement and that water in itself is an endless loop where its true start is indistinguishable from its ending.
Or from another perspective, it's like a momentary wavelet on an inexpressibly vast ocean asking who it is. Karma, ignorance, slightly saddened love, a bubble in a stream, a phantasm, a dream?
Traditionally, a study of Dependent Origination is one of the best companion teachings that Buddhism offers in how to relate to the answer.
how
In Vancouver, crows often nested in trees overhanging the neighborhood side walks. Getting dive bombed by protective crows was routine for a couple of months every year and even the mail service could be stopped for some homes where more aggressive crows were scaring the mail delivery people.
Nest-protecting Crows will usually only attack at someone's head from behind where they can get in and out safely and dish out surprise strikes with relative impunity. They do the same with other predator's as well.
Years ago I learned that if you turn around and walk backward when passing by a problem nest, the crows are too unnerved to effectively attack when they dive in from behind to effect a strike upon a cowed head and instead find a face staring right at them.
how
“There may come a moment in life when the world no longer stimulates us and we feel deeply apathetic, even abandoned. This can motivate us towards the search for our real nature beyond appearances. When we no longer find interest in activities and states, when we no longer feel much pleasure in objects and human relationships, we may find ourselves asking: “Is there something wrong with this world or with my attitude towards it?” This serious doubt can lead us to ask: “What is the meaning of existence? What is life? Who am I? What is my true nature?” Sooner or later any intelligent person asks these questions.
As we live with these questions, look at them closely, we become aware that the “me” always seems to be at the center of things playing several roles: “I am cold. I am tired. I am working.” With a more open-minded alertness it becomes apparent that the body feels cold, tired, or is working, not “I.” In the same way when we look at states: “I wish. I am depressed. I remember. I am bored,” we see that we have identified ourselves with the thought or feeling. In looking at this relation between the I and its qualifications it becomes obvious that we have taken it for granted and believe ourselves to be this “me.”
This “me” has therefore no continual reality. It is a false appropriation.”
— Jean Klein
Jeroen
@Jeroen said:
I find that when I look for no-self I go quiet, words desert me as does the compassion which motivates me to teach. Perhaps it means there are layers of my being where the dharma has not yet come.
For me, the most effective route to teaching is compassion and enthusiasm, when those are present in equal measure I am more receptive to other people’s states and questions.
Was just rereading this thread and this really struck a chord with me. It reminds me of Sujata, who saved the Buddhas mortal existence by feeding him rice. He had already seen the truth of things but her act of compassion gave it its full flavour or texture or feel. Without that act of compassion, we would have lost a most precious teacher indeed.
I love Sujata.
"What lies behind us, and what lies before us, are tiny matters compared to what lies within us" - Ralph Waldo Emerson
How very true.
federica
@FleaMarket said:
Are they aggregate feelings? Are they felt in the body?
If so, how do they work with the understanding of unclinging to aggregates such as the feelings?I hear it's to be cultivated. How much is cultivated? How much is too little/much?
It's all a matter of being open to awareness ...and developing experiential understanding of the twelve links of dependent origination ....links six and seven seem to be the sticking points, (pun intended) which one needs to be aware of/pay particular attention to ....
Awareness is fundamentally non-conceptual before thinking splits experience into subject and object ...It is empty and so can contain everything including thought...It is boundless...And amazingly it is intrinsically knowing 
Shoshin1
How to Teach?
I was going to add...
"How to teach your grandmother to suck eggs"
....but thought better of it 

Anyhow....Thus have I heard....
If one puts into practice...what one is more inclined to preach (just thinking about it)
More often than not...it's the best way to teach (actions speak louder than words)...
Shoshin1