I have always liked the practical way in which Ajahn Chah was talking about meditation, from his own experience, but very much in line with the Suttas (and not so much with Ajahn Brahm's Jhana-theory):
We practice like this until we become skilled in it and it goes smoothly. The next stage is to focus awareness only on the sensation of the breath at the tip of the nose or the upper lip. At this point we aren't concerned with whether the breath is long or short, but only focus on the sensation of entering and exiting. . . . If you are contemplating skillfully on an object such as the nature of sankhāra, then the mind will experience deeper tranquility and rapture is born.
There is the vitakka and vicāra, and that leads to happiness of mind.
At this time there won't be any dullness or drowsiness. The mind won't be dark if we practice like this. It will be gladdened and enraptured. . . .This rapture will start to diminish and disappear after a while, so you can take up the initial thought again. The mind will become firm and certain with it - undistracted.
Then you go on to discursive thought again, the mind becoming one with it.
When you are practicing a meditation that suits your temperament and doing it well, then whenever you take up the object, rapture will come about: the hairs of the body stand on end and the mind is enraptured and satiated.When it's like this there can't be any dullness or drowsiness.
You won't have any doubts. Back and forth between initial and discursive thought, initial and discursive thought, over and over again and rapture comes. Then there is sukha (bliss). . .
Vitakka is picking it up, vicāra is investigating it. For example, we pick up the idea of death and then we start considering it: ''I will die, others will die, every living being will die; when they die where will they go?'' Then stop! Stop and bring it back again. When it gets running like that, stop it again; and then go back to mindfulness of the breath. Sometimes the discursive thought will wander off and not come back, so you have to stop it. Keep at it until the mind is bright and clear.
If you practice vicāra with an object that you are suited to, you may experience the hairs of your body standing on end, tears pouring from your eyes, a state of extreme delight, many different things as rapture comes. . . .
It's when the mind is tranquil. It's not ordinary mental proliferation.
You sit with a calm mind and then the initial thought comes. . . . If it's a line of thinking that's skillful and wholesome, it leads to ease of mind and happiness, and there is rapture with its attendant experiences. This rapture came from the initial and discursive thinking that took place in a state of calmness. We don't have to give it names such as first jhāna, second jhāna and so forth. We just call it tranquility.
The next factor is bliss (sukha). Eventually we drop the initial and discursive thinking as tranquility deepens. Why? The state of mind is becoming more refined and subtle.
Vitakka and vicāra are relatively coarse,
and they will vanish. There will remain just the rapture accompanied by bliss and one-pointedness of mind. When it reaches full measure there won't be anything, the mind is empty. That's absorption concentration.We don't need to fixate or dwell on any of these experiences.
They will naturally progress from one to the next. At first there is initial and discursive thought, rapture, bliss and onepointedness. Then initial and discursive thinking are thrown off, leaving rapture, bliss, and one-pointedness. Rapture is thrown off, then bliss, and finally only one-pointedness and equanimity remain. It means the mind becomes more and more tranquil, and its objects are steadily decreasing until there is nothing but one-pointedness and equanimity.When the mind is tranquil and focused this can happen.
It is the power of mind, the state of the mind that has attained tranquility.
When it's like this there won't be any sleepiness.
It can't enter the mind; it will disappear. As for the other hindrances
of sensual desire, aversion, doubt and restlessness and agitation, they just won't be present.
Though they may still exist latent in the mind of the meditator, they won't occur at this time. http://www.ajahnchah.org/book/Monastery_Confusion1.php