(Aishah (may Allah be pleased with her) reported: I asked: "O Messenger of Allah! If I realize Lailat-ul-Qadr (Night of Decree), what should I supplicate in it?" He (PBUH) 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-Tirmizi, Ibn Majah and Ahmad]

Du'a ( invocation) is an act of worship; better yet, it is the worship. If man says, "Ameen" (truly) to someone else's Du'a, it is as if he made Du'a himself. When Musa (Moses) and his brother Harun (Aaron) PBUT, appealed to Allah, Allah's response was: 

﴾"Verily, the invocation of you both is accepted.﴿ 

[Yunus, 89]

The one who believes, who bethinks of Allah's Greatness and who sees himself before Allah invoking Him, is a supplicant himself too. 

This night is the most honorable night among all nights of the year. It is al-Qadr Night:

﴾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).﴿ 

[Al-Qadr, 1-3]

If you rightly establish a connection with Allah in al-Qadr night, turn to Him and make Du'a to Him, it will be a night that is better than offering your acts of worship formally for eighty years, given the night of al-Qadr is better than a thousand months (which equals eighty years).