Ibn al-Qayyim enumerated some of the factors that bring about tranquility:
1. Islamic Monotheism, worshipping Allah exclusively without associating any partners with him [in worship], and without associating any partners with Him in all qualities that belong to Him…
That is the proper way to make dua. First praise Allah(swt) and send blessings to Prophet Muhammad (saws), and then ask Allah(swt) for what you want. A great way to praise Allah(swt) is to use His 99 names; which is why it is important to memorize the names, know the meaning, and implement them in your life.
It was narrated that Faddalah ibn ‘Ubayd said: The Prophet (peace and blessings of Allah be upon him) said, “When any one of you has finished praying (and makes dua), let him start by praising Allah, then let him send blessings upon the Prophet (peace and blessings of Allah be upon him), then after that let him ask for whatever he wants.” Al-Albani said: it is a saheeh hadeeth.
A great example is in Surah Fatiha, where first you praise Allah(swt), calling Him Ar-Rahman and Ar-Rahim, and then you ask for what you want, which is to be guided on the straight path.
Surat Al-Fātiĥah (The Opener)
In the name of Allah , the Entirely Merciful, the Especially Merciful.
[All] praise is [due] to Allah , Lord of the worlds -
The Entirely Merciful, the Especially Merciful,
Sovereign of the Day of Recompense.
It is You we worship and You we ask for help.
Guide us to the straight path -
The path of those upon whom You have bestowed favor, not of those who have evoked [Your] anger or of those who are astray.