Praise be to Allah
Imam Ibn al-Qayyim (may Allah have mercy on him) said:
From this it will be clear that there is an etiquette and rulings which must be fulfilled, in the du’a and in the person making the du’a. There are also things that may prevent the du’a reaching Allah subhanahu wa ta’ala or being answered – these things must be removed from the person making the du’a and from the du’a. When all of these conditions are fulfilled, then the du’a may be answered.
1. Sincerity in making du’a
This is the most important condition. Allah subhanahu wa ta’ala has commanded us to be sincere when making du’a, as He says (interpretation of the meaning):
“So, call you upon Allah making worship pure for Him (by worshipping none but Him and by doing religious deeds sincerely for Allah’s sake only and not to show off and not to set up rivals with Him in worship).” [Ghaafir 40:14]
Sincerity in du’a means having the firm belief that the One upon Whom you are calling – Allah, may He be glorified and exalted – is alone Able to meet your need, and it also means avoiding any kind of showing off in your du’a.
2. Repentance and turning back to Allah
Sin is one of the main reasons why du’as are not answered, so the person who is making du’a should hasten to repent and seek forgiveness before he makes du’a. Prophet Nuh [Noah] ‘alayhi salaam said:
“Ask forgiveness from your Lord, verily, He is Oft-Forgiving; He will send rain to you in abundance, And give you increase in wealth and children, and bestow on you gardens and bestow on you rivers.” [Nuh 71:10-12]
3. Beseeching, humbling oneself, hoping for Allah’s reward and fearing His punishment
This is the spirit, essence and purpose of du’a. Allah says (interpretation of the meaning),
“Invoke your Lord with humility and in secret. He likes not the aggressors.”
4. Urgently beseeching and repeating the du’a, without getting exasperated or bored
This is achieved by repeating the du’a two or three times. Restricting it to three times is preferable, in accordance with the Sunnah of the Prophet salAllahu ‘alayhi wa sallam. Ibn Mas’oud radhiAllahu ‘anhu narrated that the Prophet salAllahu ‘alayhi wa sallam liked to say a du’a three times and ask for forgiveness three times. [Abu Daw’oud and an-Nasa’i]
5. Making du’a at times of ease, and saying more du’as at times of plenty
The Prophet salAllahu ‘alayhi wa sallam said, “Remember Allah during times of ease and He will remember you during times of hardship.” [Ahmad]
6. Seeking to draw closer to Allah by calling upon Him by His Most Beautiful Names
and Sublime Attributes at the beginning of the du’a or at the end. Allah says (interpretation of the meaning),
“And (all) the Most Beautiful Names belong to Allah, so call on Him by them.” [al-A’raf 7:180]
7. Choosing the clearest and most concise words and the best of du’as
The best of du’as are the du’as of the Prophet salAllahu ‘alayhi wa sallam, but it is permissible to say other words according to the specific needs of a person.
Other aspects of the etiquette of making du’a, although they are not waajib [obligatory], are: to face the Qiblah; to make du’a in a state of tahaarah [purity]; to start the du’a with praise of Allah and blessings upon the Prophet salAllahu ‘alayhi wa sallam. It is also prescribed to raise the hands when making du’a.
One of the things that helps to bring a response to du’a is to seek the best times and places.
Among the best times is the time just before Fajr (dawn), the last third of the night, the last hour of Jumu’ah (Friday), when rain is falling, and between the Adhaan and iqaamah.
Among the best places are mosques in general, and al-Masjid al-Haraam [in Makkah] in particular.
Among the situations in which du’a is more likely to be answered are: when one is mistreated or oppressed, when one is traveling, when one is fasting, when one is in desperate need, and when a Muslim makes du’a for his brother in his absence.
Slightly modified – the original question can be read at islamqa.info