وَقَالَ رَبُّكُمُ ادْعُونِي أَسْتَجِبْ لَكُمْ
And your Lord says, “Call upon Me; I will respond to you.” Indeed, those who disdain My worship will enter Hell [rendered] contemptible.
Holy Qur’an [40:60]
Prayer is an important point of focus of all religions, especially when it comes to Islam – hence the five obligatory prayers every Muslim is required to fulfill. The AhlulBayt, our role models, have given utmost importance to the role of prayer in the life of every Muslim in their speeches by even mention the etiquettes of, and the optimal times of the day, for supplicating. This persistence by the AhlulBayt on habitual supplication with Allah is due its ability to compensate for the lack of spiritual, mental, and physical comfort which arises from time to time in one’s life – especially within the 21st century, the age of materialistic greed and spiritual bankruptcy.
الَّذِينَ آمَنُواْ وَتَطْمَئِنُّ قُلُوبُهُم بِذِكْرِ اللّهِ أَلاَ بِذِكْرِ اللّهِ تَطْمَئِنُّ الْقُلُوبُ
Verily in the remembrance of Allah do hearts find rest!
Holy Qur’an [13:28]
I see it crucial to mention that the effects and benefits of supplications, remembrances (dhikr) and recommended (mustahab) prayers are attained by man once certain criterions, such as etiquettes of supplications, pure intentions and furthering one from sin, are met.
اللَّهُمَّ اغْفِرْ لِي الذُّنُوبَ الَّتِي تَحْبِسُ الدُّعَاءَ
O Allah forgive me for those sins which hold back supplication!
When is it most suitable to supplicate?
Although it is praiseworthy to persistently supplicate with Allah, conferring to certain narrations, our noble role models have pointed out precise times of the day where prayers are more likely to be accepted. According to a tradition in Bihar-al-Anwar, Imam Sadiq (as) stated that the supplications made after prayer is accepted . Furthermore, it is narrated from the Holy Prophet (sa) that the best time to supplicate is early in the morning. Moreover, Imam Sadiq (as) has said that supplication before sunrise and sunset is a tradition and obligatory (wajib) order of ours.
Lastly, Imam Sadiq (as) has said in Bihar-al-Anwar that there are three times, that if prayers are made within, they will be accepted and fulfilled. 
- After an obligatory (wajib) prayer
- When it’s raining
- While the appearing of miraculous signs from God to his servants
As we can see, the AhlulBayt have prescribed specific times for when supplications are most likely to be accepted. It should however be needless to say that one ought to supplicate with Allah at all times possible so as not to miss out on the benefits of heart-to-heart supplications with Allah.
Conditions for Supplicating
- Plead guilty to having sinned
The very first step for repentance and supplication is admitting to your mistakes and shortcomings. Upon arriving at the stage of disclosing your sins to Allah (in the form of admittance and regret) and eagerly craving improvement, you mentally prepare for spiritual development.
اللَّهُمَّ اغْفِرْ لِي كُلَّ ذَنْبٍ أَذْنَبْتُهُ وَكُلَّ خَطِيئَةٍ أَخْطَأْتُهَا
O Allah, forgive me for every sin I have committed and for every mistake I have made!
- Gratefulness for blessings
Very often than not, those who experience difficulties in life divert their problems onto God instead of looking within to search what caused their adversity. Regardless of your situation, poor or rich, healthy or ill, young or old, wise or ignorant, fortunate or unfortunate, you must always count the other enumerate amount of blessings Allah has given you – the right to life being universally relatable blessing.
وَآتَاكُمْ مِنْ كُلِّ مَا سَأَلْتُمُوهُ ۚ وَإِنْ تَعُدُّوا نِعْمَتَ اللَّهِ لَا تُحْصُوهَا ۗ إِنَّ الْإِنْسَانَ لَظَلُومٌ كَفَّارٌ
“And He gave you from all you asked of Him. And if you should count the favor of Allah, you could not enumerate them. Indeed, mankind is [generally] most unjust and ungrateful.”
Holy Qur’an [14:34]
- Sending blessing upon the Holy Prophet (saws) and his family
- Supplicating with Allah and asking for your needs (hajat)
If your supplication is accepted
- Be careful pride does not overtake you by saying: “Since my request was fulfilled, I must be very dear to God!”
وَيَوْمَ الْقِيَامَةِ تَرَى الَّذِينَ كَذَبُوا عَلَى اللَّهِ وُجُوهُهُمْ مُسْوَدَّةٌ ۚ أَلَيْسَ فِي جَهَنَّمَ مَثْوًى لِلْمُتَكَبِّرِينَ
Is there not in Hell an abode for the proud?
Holy Qur’an [39:60]
- Humbly express gratitude to Allah for having your supplications answered by offering a two unit (rakat) Salat al-Shukr (prayer of thanks). 
- Continue to supplicate with your Lord and do not abandon your prayers as soon as your requests are fulfilled.
أفْضَلُ النَّاسِ مَنْ عَشِقَ العِبَادَةَ فَعَانَقَهَا وأحَبَّهَا بِقَلْبِهِ وَبَاشَرَهَا بِجَسَدِهِ وَتَفَرَّغَ لَهَا فَهُوَ لاَ يُبَالِي عَلَى مَا أصْبَحَ مِنَ الدُّنْيَا؛ عَلَى عُسْرٍ أمْ عَلَى يُسْرٍ.
The Messenger of Allah (sa) has stated about worship: “The best man is the one who loves worshipping Allah in his heart, does it by his limbs, and leaves other activities for it, not fearing worldly hardships.”
If your supplication isn’t answered
- Do not despair from God’s mercy; because not having your supplications answered may be as a result of your sins (which acted as a barrier).
اللّهُمَّ اغْفِرْ لِيَ الذُّنُوبَ الَّتِي تَحْبِسُ الدُّعأَ
O Allah! Forgive me as my sins would hinder my supplication
- Do not abandon constant supplication.
يَا أَيُّهَا الَّذِينَ آمَنُوا اسْتَعِينُوا بِالصَّبْرِ وَالصَّلَاةِ ۚ إِنَّ اللَّهَ مَعَ الصَّابِرِينَ
O you who have believed, seek help through patience and prayer. Indeed, Allah is with the patient.
Holy Qur’an [2:153]
- To be content with the result of your supplication (as Allah is enough as a Disposer of Affairs), for this very contentment may perhaps be the cause for the acceptance of your supplication.
فَإِذَا عَزَمْتَ فَتَوَكَّلْ عَلَى اللَّهِ ۚ إِنَّ اللَّهَ يُحِبُّ الْمُتَوَكِّلِينَ
…Then when you have taken a decision, put your trust in Allah, certainly, Allah loves those who put their trust (in Him).
Holy Qur’an [3:159]
As previously stated, supplication and prayer is of paramount importance in Islam because of its essential aspect of reminding us of a Greater Entity who we’ve come from and will return to. This remembrance in itself suffices to humble one in realizing how limited and powerless we really are. The path to God isn’t complicated, it simply takes initiative and a sincere intention, the rest? Leave it to God.
وَقَالَ رَبُّكُمُ ادْعُونِي أَسْتَجِبْ لَكُمْ
And your Lord said: Supplicate to Me, I shall answer you.
Holy Qur’an [40:60]
وَادْعُوهُ مُخْلِصِينَ لَهُ الدِّينَ
And supplicate to Him, making your religion sincerely for Him alone.
Holy Qur’an [7:29]
 Bihar-al-Anwar, Volume 59, p1. Bihar al-Anwar, Volume 90, p343  Usool-al-Kafi: 2/ 83, Bab Al-Ibada, tradition 3
In addition to the cited sources, the author, a past Islamic studies student, has referenced a Farsi text, Dhikr Haye Asemani. This text is based on the advice of great ulema likened to Ayatullah Bahjat, Ayatullah Abdul Karim Kashmiri.