How to bow correctly: Patitthitapanca

In the Theravadan tradition of Buddhism, there is typically a form of prostration used that is known as five-point veneration (Pali: patitthitapanca) or five-limbed prostration (Pali: pañc'anga-vandana) where the two palms and elbows, two sets of toes and knees, and the forehead are placed on the floor.
In contrast to prostrations in the Tibetan tradition, the prostration does not start while standing, but from an already kneeling position.

The complete movement is done as fluidly and gracefully as possible. As an act of humility it is an offering which is made as beautiful as one can. When bending forward this is done from the hips, not the knees, to avoid the tendency for the backside to stick up in the air - not very elegant.

Begin by kneeling, facing towards what you are bowing to.
The usual posture is to rest on the heels with the toes 'pointing' - as opposed to laying flat on the floor.

Raise the hands in the gesture of the Wai.
The hands form the shape of a lotus bud - a potent image in itself, rich with symbolism. The interlocking ten fingers represent the ten Paramittas - the virtues.

The hands can then be raised to the forehead - either directly or in three stages: first to the heart center, then the lips then the forehead.
This three-fold gesture can be seen as bowing with body, speech and mind, the three 'doors' of action in the world.
The hands and head are then lowered toward the floor. There should be a clear awareness of what one is bowing to.
When bowing before a sacred object such as a Buddha statue, one usually bows three times, recalling with the first bow the Buddha, then the Dhamma and then the Sangha. As part of ones daily practice, one typically prostrates before and after chanting and meditation.

The final position has five-points of the body in contact with the ground - the toes, knees, elbows, hands and fore-head.

In Thailand, traditionally, each of the three aforementioned prostrations are accompanied by the following Pali verses:

First Prostration:
Araham samma-sambuddho bhagava Buddham bhagavantam abhivademi.
The Noble One, the fully Enlightened One, the Exalted One, I bow low before the Exalted Buddha.

Second Prostration:
Svakkhato bhagavata dhammo Dhammam namassami.
The Exalted One's well-expounded Dhamma I bow low before the Dhamma.

Third Prostration:
Supatipanno bhagavato savakasangho sangham namami.
The Exalted One's Sangha of well-practiced disciples I bow low before the Sangha.