Allah, the Exalted, says:

"Verily, We have sent it (this Qur'an) down in the Night of Al-Qadr (Decree). And what will make you know what the Night of Al-Qadr (Decree) is? The Night of Al-Qadr (Decree) is better than a thousand months (i.e., worshipping Allah in that night is better than worshipping Him a thousand months, i.e., 83 years and 4 months). Therein descend the angels and the Ruh [Jibril (Gabriel)] by Allah's Permission with all Decrees. (All that night), there is peace (and goodness from Allah to His believing slaves) until the appearance of dawn.'' (97:1-5)

"We sent it (this Qur'an) down on a blessed night [(i.e., the Night of Al-Qadr, Surah No:97) in the month of Ramadan, the 9th month of the Islamic calendar]. Verily, We are ever warning [mankind that Our Torment will reach those who disbelieve in Our Oneness of Lordship and in Our Oneness of worship]. Therein (that night) is decreed every matter of ordainments (i.e., the matters of deaths, births, provisions, and calamities for the whole (coming) year as decreed by Allah). As a Command (or this Qur'an or the Decree of every matter) from Us. Verily, We are ever sending (the Messengers). (As) a Mercy from your Rubb, Verily! He is the All-Hearer, the All-Knower.'' (44:3-6)

Abu Hurairah (radiallahu anh) reported: The Prophet (salallahu alayhi wa sallam) said, "Whosoever performs Qiyam during Lailat-ul-Qadr (Night of Decree), with Faith and being hopeful of Allah's reward, will have his former sins forgiven.''
[Al-Bukhari and Muslim].

`Aishah (radiallahu anha) reported: The Messenger of Allah (salallahu alayhi wa sallam) used to seclude himself (in the mosque) during the last ten nights of Ramadan. He would say, "Search for Lailat-ul-Qadr (Night of Decree) in the last ten nights of Ramadan.''
[Al-Bukhari and Muslim].

`Aishah (radiallahu anh) reported: The Messenger of Allah (salallahu alayhi wa sallam) used to observe I`tikaf in the last ten days of Ramadan and say, "Seek Lailat-ul-Qadr (Night of Decree) in the odd nights out of the last ten nights of Ramadan.''
[Al-Bukhari].

We learn from this Hadith that Lailat-ul-Qadr occurs in any of the five odd nights - 21st, 23rd, 25th, 27th and 29th - of the last ten nights of Ramadan. Its exact date has not been revealed for the reason that people keep themselves awake for prayer for a larger number of nights. Had its date been fixed, people would have kept awake for prayer only on that night.

`Aishah (radiallahu anha) reported: When the last ten nights (of Ramadan) would begin, the Messenger of Allah (salallahu alayhi wa sallam) would keep awake at night (for prayer and devotion), awaken his family and prepare himself to be more diligent in worship.
[Al-Bukhari and Muslim].

'Aishah (radiallahu anha) reported: The Messenger of Allah (salallahu alayhi wa sallam) used to strive more in worship during Ramadan than he strove in any other time of the year; and he would devote himself more (in the worship of Allah) in the last ten nights of Ramadan than he strove in earlier part of the month.
[Muslim].

One should keep oneself awake for prayer, worship and glorification of Allah in the last ten nights of Ramadan so that one can attain the blessings of Lailat-ul-Qadr.
One should also persuade his family members to keep themselves awake for prayer and worship in the last ten odd nights of Ramadan so that they can also make efforts to please Allah.
I`tikaf (seclusion in the mosque for prayers) in the last ten days of Ramadan is also a meritorious act for its being a practice of the Prophet (salallahu alayhi wa sallam).

`Aishah (radiallahu anha) reported: I asked: "O Messenger of Allah! If I realize Lilat-ul-Qadr (Night of Decree), what should I supplicate in it?'' He (salallahu alayhi wa sallam) replied, "You should supplicate: Allahumma innaka `afuwwun, tuhibbul-`afwa, fa`fu `anni (O Allah, You are Most Forgiving, and You love forgiveness; so forgive me).''
[At-Tirmidhi].