This is the most important query on Hazrat Mahdi (a.t.f.s.) because of its practical aspects in the commandments and doctrines of Islam. Islam never supports mere theoretical matters. In one tradition, Imam Sadiq (a.s.) says:
“The faith should completely be materialized in behavior and practice” 
Thus, we can say that during ‘Ghaibat’ (concealment), the duties of Shias are linked to action. They should endeavour during this period of severe test and conspiracies. A Shia should keep himself from the dangers and then play the role of rectifying the affairs in the society as much as he can.
In this regard, the Imams have given 3 important recommendations:
‘Entezar’ (awaiting), looking forward for ‘Zohour’ (manifestation), that will result in rectification of the global affairs.
Being careful about one’s deeds and one’s special responsibilities.
Reciting some of the supplications and invocations
Regarding the first order, the Imams have praised very much the act of ‘Entezar’. One tradition says:
“The most excellent worship is to await ‘Faraj'(Reappearance).”
“The one who awaits ‘Zohour’ and ‘Faraj’ is like a martyr soaked in blood on the way of Allah.” 
About the second duty, the Imams have laid stress on belief in Allah, acceptance of the holy prophet’s message, acknowledgment of divine commandments, submission before the ‘Wilayat’ (authority) of Imams, growing weary of their enemies, adopting piety, endeavouring on path of worship etc. For instance, Imam Baqir (a.s.) has said:
“Worship of Allah is the offshoot of His Ma’refat.”
Narrator asks: ‘What is Ma’refat of Allah?’
Imam replied: ‘Belief in Allah, and His Apostle and Wilayat of Ali and following him and the guided Imams and growing weary of their enemies. Allah is recognized in this manner.”
About the third duty too, we may mention such recommended invocations like :
اللهم كن لوليك………
اللهم عرفني نفسك…….
سلام علي آل ياسين….
The holy prophet (s.a.w.a.) has called the believers during the period of ‘Ghaibat’ as his brothers and praised them excessively.
During ‘ghaibat’, we should get ‘Ma’refat of Allah, Ma’refat of His Prophet and Ma’refat of Imam. We should also act upon their commands and exalt the name of Hazrat Mahdi (a.t.f.s.) and spread his thoughts.
We can summarize most of the duties into two fundamental fields: (comprising of belief and practice)
To accept in the necessity of Hujjat (a.t.f.s.)
Recognition of Hazrat Mahdi (a.t.f.s.), striving to increase this recognition and reciting the Dua-e-Ma’refat
(اللهم عرفني نفسك)
Renewal of covenant to acknowledge monotheism, prophethood and Wilayat and presenting one’s belief before him (Ziarate-Aale-Yasin).
Following and obeying Hazrat Mahdi strictly.
Looking forward for his ‘Zohour’ and ‘Faraj’ and reciting Dua-e-Faraj in prayers.
State of carefulness in safeguarding the bounds of Allah and the immaculate ones.
Seeking his help at times of hardship and reciting the Dua “إلهي عظم البلاء ”
To endeavour and recite prayers for remaining steadfast and recitation of Dua-e-Ah’d at dawns.
Creating love and affection in one’s heart and expressing true love before him:
a) To honour him by sending salutation and reciting prays on Friday and other days
b) Standing on feet after hearing his special title (Qaem) and requesting Allah for hastening his Zohour.
c) Giving priority to Hazrat Mahdi in one’s prays.
d) Reciting Ayat’ul-Kursi after every salat and giving charity for his health and well-being.
e) Gifting him with prayers and recommendable acts like recitation of Qur’an, Haj-e-Umra, Ziarat of Imams, etc.
All of these can be summarized in the term“Readiness” . Since this term implies preparedness in all aspects, which the waiting person should always preserve, until he acts whenever the need arises.