I`tikaf is the seclusion and staying in the Masjid with the intention of becoming closer to Allah by doing constant remembrance, glorification and worship of Allah Ta’aala.
One should perform as many Nafil prayers as possible and recite much of the Qur’an and its meanings, read books on Islam and keep ones lips moist with the constant glorification and remembrance of Allah ta’aala.
`Aishah radhiya Allahu `anha reported that the Prophet, salla Allahu alaihi wa sallam, “Used to perform i’tikaf in the last ten days of Ramadan until Allah the Mighty and Majestic, took him. (Bukhari and Muslim)
Abu Said reported that the Prophet (S) said: “Whoever makes I`tikaf with me is to make I’tikaf during the last ten [nights].” (Bukhari)
We can also do what’s called Nafil I’thikaf where one can obtain reward for as long as one is in the Masjid even if it is for a short while.
So every time we enter the Masjid we should make intention of doing Nafil I’thikaf for as long as we are in the Masjid we will get rewarded inshallah depending on how long we stay. If we don’t stay at the Masjid for the full ten days then we should at least strive to stay at the Masjid as much as possible during the odd nights or last 5-7 days.
Allah’s Messenger used to exert himself in devotion during the last ten nights to a greater extent than at any other time.” (Muslim).