Associated with this are three other prayers designated to arouse G-d's mercy and increase his blessing. These are the Confession the Thirteen Attributes and the "Falling on One's Face" [in the Tachanun].
- From The Way of G-d, R. Moshe Chaim Luzzato, pg 307
The purpose of the confessio nis to prevent our accusers from speaking out and causing the service to be ast aside.
We then recite the thirteen attributes of Mercy because they have the power to cause G-d to be grasped through His attribute of mercy, so that through his superior Authority, He should overlook sin and have compassion even when merit is lacking.
The "Falling on One's Face" in Tachanun is also a high degree of self subjugation before G-d. It therefore has the power to appease the attribute of justice and arouse great mercy.lacking. G-d's sustenance can then be transmitted with blessing and abundance.
This is the general arrangement of the daily service. The precise order of Psalms, Biblical readings and other details depends on the details of what the service is meant to accomplish.