Eve of 'Arafah: is the Eve of the ninth of Dhu Al-Hijjah, and it is a blessed night, a night for invocations, repentance and the supplication in it is answered. The one who obey the Almighty during it has the reward of hundred and seventy nights of accepted repentance. Its recommended acts are:
First: reading the supplication of "O my Allah! O He who sees clearly through what hearts and minds desire secretly, makes good and settles all complaints, knows full well the ins and outs of whatever is kept undisclosed, the ultimate fulfillment of all desires!..." the supplication narrated in Mafatih Al-Jinan p333, It is narrated that he who read this supplication on the eve of 'arafah or the eves of fridays, God forgive him.
Second: read the ten tasbeehat thousand times: "Glory be to Allah, before everyone (glorifies Him). Glory be to Allah, after everyone (glorifies Him). Glory be to Allah, when everyone. (glorifies Him)..." Mafatih Al-Jinan p:341
Third: Reading the Supplication: "O my Allah! Many a man takes pain, makes compromises, uses artifices, comes to terms, to draw attention of other men in hope of profit and gain, kindness and indulgence, but unto You.." Mafatih al-Jinan p:62
Fourth: The Ziyarat of Imam Al-Hussayn (peace be upon him). Mafatih al-Jinan p:547.
The day of 'Arafah: The ninth day of Dhu Al-Hijjah, and it is one of the greatest Eids even though it wasn't called a Eid, it is a day in which Allah has called his slaves to obey and worship Him and has extended to them tables of kindness and generosity, Satan during it is vile, wretch and angry more than any other time.
It is narrated that Imam Zayn Al-'abideen (peace be upon him) has heard a man begging from people on the day of 'Arafah and said: Woe unto you that on a day like this you are asking from other than God. This is a day when the mercy and grace of Allah reaches (even the fetus in the womb."
There are many recommended acts to perform during this day that are:
First: Have a Ghusl/ purification bath
Second: Recte the special Ziyarat of Imam Al-Hussayn (peace be upon him) on this day, and this is the most important act. The Almighty God looks at the visitors of Imam Al-Hussayn (peace be upon him) on the day of 'Arafah before looking at the standing on the mount of 'Arafah.. Yes this is the least that Aba Abdillah (peace be upon him) deserves, as without his holy revolution and sacrifice, 'Arafah and Hajj will be forgotten. So the Almighty upheld the matter of the master of martyrs (peace be upon him) as he was the one who respected the saint house when the Umayyad planed to shed the sacred blood in the sacred house on the sacred month. This is why it is one of the greatest Eids even though it wasn't called a Eid, it is a day in which Allah has called his slaves to obey and worship Him and has extended to them tables of kindness and generosity, Satan during it is vile, wretch and angry more than any other time.
Imam As-Sadeq (peace be upon him said: He who visits the tomb of al-Hussayn (peace be upon him) on the day of 'Arafah, he shall be granted to reward of thousand of thousand Hajj with the Qa'im -i.e Imam Al-Mahdi (peace be upon him and may allah hasten his holy reappearance)- and thousand of thousand 'Umrah with the Messenger of Allah (prayers and Allah's peace be upon him and his holy Household), freeing thousand of thousand slaves, equipping thousand of thousand of horses in the path of Allah and the Almighty God will call him: He is my servant who has testified to My Promise and is certain about it.’ The angels shall proclaim, ‘So and so is the testifying servant. Allah has purified and cleansed him over His Arsh.’ On the earth, he shall be called as Karubi."
Third: Pray after the obligatory prayer of 'Asr before starting the supplications of 'Arafah two 2 Raka’t under the sky, acknowledging his sins to gain the reward of 'Arafah and so his sins will be forgiven and then start reading the supplications of this day (Mafatih Al-Jinan)
Fourth: Reciting the supplication narrated by the Holy Prophet (prayers and Allah's peace be upon him and his holy Household): "I Glory be to He whose Arsh is in the heavens! Glory be to He whose Will operates in the earth!.." Mafatih Al-Jinan p:339
Fifth: Reciting the supplication of Imam Zayn Al-'Abideen on 'Arafah day
Sixth: Reciting the supplication of Imam al-Hussayn (peace be upon him) on this blessed day: "Praise be to Allah Whose determination cannot be repelled by anything..." (Mafatih Al-Jinan p:343)