G'd says in the Qur'an (17:110): Say! Call upon G'd or call upon the Merciful, by whatever name you call HIM, to HIM belongs the most beautiful names. Neither say your pray loudly, nor too softly, but seek a middle course between.
Every need of a human or action that is clocked into the creation, G'd is the supplier and controller of everything. To make a closer connection with G'd, we can sincerely invoke one of HIS names that connects with what we are begging or asking HIM for.
If one is seeking forgiveness, call upon HIM that is most forgiving. If one is seeking justice, call upon HIM that is most just.
Polytheists believe in a big deity, but they attribute the specific powers of G'd as smaller entities called demi-gods to reach the big deity. This is a misunderstanding of HIS absoluteness, and that HE manifests these varying aspects within the universe.
Audio links of beautiful du`aat:
And surely G'd knows best.