It is recommended to supplicate often during all times, especially during the month of Ramadan, in the last ten nights, and during the odd nights of it even more so. It is recommended that one say the following supplication a lot:
“O Allah! Verily, You are the Oft-Pardoning, You love to pardon, so pardon me.”
This is due to what Imam Ahmad recorded from `A’ishah (Radhiallahu Anha), that she said, “O Messenger of Allah (Sallallahu Alayhi Wasallam)! If I find the Night of Al-Qadr what should I say” He replied,
«”قُولِي: “اللْهُمَّ إِنَّكَ عَفُوٌّ تُحِبُّ الْعَفْوَ فَاعْفُ عَنِّي»
[Allaahumma Innaka Afuwwun Tuhibbul Afwa Fa’fu Annee ]
(Say: “O Allah! Verily, You are the Oft-Pardoning, You love to pardon, so pardon me.”)
At-Tirmidhi, An-Nasa’i and Ibn Majah have all recorded this Hadith. At-Tirmidhi said, “This Hadith is Hasan Sahih.”
Al-Hakim recorded it in his Mustadrak (with a different chain of narration) and he said that it is authentic according to the criteria of the two Shaykhs (Al-Bukhari and Muslim).
An-Nasa’i also recorded it.