ביטול היש

Tefilla is "bitul ha-yesh" - a complete nullification of myself and my own needs and a connection to the Divine will. A person is supposed to come to a recognition of the fact the we can't acheive anything in life without Hashem's help. The gemara says [bk 92] that if you need something and you daven that your friend should get the same thing - you will be answered first. The reason is that you were successfully mevatel your "yesh" - your own personal needs and instead focused on your friend. This serves as a merit to have your own needs satisfied first.

[Sefer Zikaron for Rav Dessler page 33]