Du'a..

THE MERITS AND IMPORTANCE OF DUA

The purpose of man's creation is to worship Allah (swt).
Allah says:

    وَمَا خَلَقْتُ ٱلْجِنَّ وَٱلْإِنسَ إِلَّا لِيَعْبُدُونِ 
(الزاريات : ٥٦)
  
“ I have not created jinn and men except that they may worship me.” 
                            (Az Zariyat: 56)

To invoke Allah (swt) is also worship. As the Prophet (Peace be upon him) stated:

(الدُّعَــــــــاءُمُخُّ الْعِبَــــــــادَةِ (التـــــرمذي 

“Dua is the essence of worship.” 
                              (Al-Tirmidhi)

Allah says:

وَإِذَا سَــــأَلَكَ عِبَادِى عَنِّـــــى فَإِنِّـــــــــــى 
قَرِيبٌ ۖ أُجِيبُ  دَعْـوَةَ ٱلدَّاعِ إِذَا دَعَـــــــانِ 
 (البقرة:١٨٦)

“ O Mohammad (PBUH)  when my slaves ask you concerning Me, (then) say indeed I am near, I respond to the Duas of the supplicant when he calls on Me.”

ETIQUETTES OF DUA

◉ Sincere intention.

◉  To begin with praise and glorification of Allah and to send blessings on the Prophet (PBUH) and to end the dua in the same manner.

◉  To invoke with the certainty that it will be accepted.

◉  Do not ask from anyone other than Allah.

◉  Invoke for oneself first and then for others.

◉  Seek Forgiveness from Allah while acknowledging ones sins.

◉  Acknowledge the blessings of Allah upon oneself and to show gratitude.

◉  To make dua with full concentration as Allah does not accept a dua of a heedless heart.

THE TIMES OF ACCEPTANCE OF DUA

◉ At the end of obligaratory (Farz) prayer.

◉ Between the Azan and the Iqamat.

◉ At the time of Tahajud.

◉ In prostration.

◉ When it is raining.

◉ Travelling on a journey.

◉ A specific time during Friday.

◉ In the battlefield.

◉ At the time of pre-dawn meal (sehri).

◉ When fasting.

◉ When opening the fast.

◉ The night of power and destiny.

◉ When drinking Zamzam.

◉ On the day of Arafat and while standing in the plain of Arafat.

◉ After recitation of the Quran.

It is proved from Ahadith that Allah (swt) accepts the Dua at these times.

WHY DUA IS NOT ACCEPTED?

Once Ibrahim bin Adham was asked, we invoke Allah but our duas are not answered. What is the reason for this? So he replied:

◉ You recognized Allah but did not give His right.

◉ You read the Quran but did not act upon it.

◉ You claimed to love the Prophet (Peace be upon him) but did not act upon his sunnah.

◉ You desired Paradise but did not do those deeds in order to enter it.

◉ You claimed to have enmity for shaytaan but did not oppose him.

◉ You acknowledged the reality of death but did not prepare for it.

I've taken this from my du'a applications :)