All praise is for Allah who blessed us with Dua’a – supplication – and promised to accept it. I bear witness that there is no god but Allah and I bear witness that Muhammad is our messenger.

Allah said:
 قال تعالى: يَا أَيُّهَا الَّذِينَ آمَنُوا اتَّقُوا اللَّهَ وَلْتَنظُرْ نَفْسٌ مَّا قَدَّمَتْ لِغَدٍ وَاتَّقُوا اللَّهَ إِنَّ اللَّهَ خَبِيرٌ بِمَا تَعْمَلُونَ
O you who believe! Fear Allah and keep your duty to Him . And let every person look to what he has sent for the tomorrow, and fear Allah .(59:18)

O believers, Allah ordered his slaves to offer Duaa and he promised to accept Duaa.

as He said:
 فقال سبحانه وتعالى: وَقَالَ رَبُّكُمْ ادْعُونِي أَسْتَجِبْ لَكُمْ
And your lord said invoke Me, believe in my oneness, I will respond to your invocation.(2:186)

Dua’a, supplication is a special worship; the slaves feel the poverty and the need for God.

Our messenger (peace be upon him) said:
قال رسول الله صلى الله عليه وسلم: "الدُّعَاءُ هُوَ العِبادَةُ "
Supplication (Duaa) is worship.

One of the ways to have accepted (Duaa) is to remember and invoke Allah at the good times.
قال رسول الله
صلى الله عليه وسلم: " مَنْ سَرَّهُ أَنْ يَسْتَجِيبَ اللَّهُ لَهُ عِنْدَ الشَّدَائِدِ وَالْكُرَبِ فَلْيُكْثِرِ الدُّعَاءَ فِي الرَّخَاءِ
Anybody hopes that Allah accepts his Duaa in difficulties; he must call for a lot in good times.

Also our messenger (peace be upon him) said:
 قال رسول الله
صلى الله عليه وسلم: ادْعُوا اللَّهَ وَأَنْتُمْ مُوقِنُونَ بِالإِجَابَةِ
Call Allah while you realize and believe that he will answer.

And one of the ways to seek accepted Duaa is to start it with thanking Allah and praising him. This is besides giving blessing for our messenger Muhammad (peace be upon him).

Omar Ibn  Alkatab said that Duaa is still standing between earth and heaven without rising up until giving blessings for our messenger Muhammad (peace be upon him) .

Our messenger said:
 قال رسول الله صلى الله عليه وسلم: إِنَّ اللَّهَ طَيِّبٌ لاَ يَقْبَلُ إِلاَّ طَيِّباً
That God is good and accepts only a good.

Then he (peace be upon him) told us about a man that may travel long travel, but his food, drink, and his clothes, were earned illegally - from haram, so God will not respond to his prayer.

Another way of gaining accepted Duaa is to call Allah for one’s brother in his absence.
قال رسول الله
صلى الله عليه وسلم: دَعْوَةُ الْمَرْءِ الْمُسْلِمِ لأَخِيهِ بِظَهْرِ الْغَيْبِ مُسْتَجَابَةٌ
Muslim’s One call to his Muslim brother is answered and accepted.