1- Observing the night prayer (Quiyam)
The Messenger of Allah, peace be upon him, said: "Whoever, with faith and he intention to earn the reward, observes the fast of Ramadan and spends some part of the night in remembrance of Allah, is forgiven for all the sins he has committed so far." (Bukhari and Muslim)
A) Providing food or money.
Narrated Ibn 'Abbas: Allah's Apostle was the most generous of all the people, and he used to reach the peak in generosity in the month of Ramadan when Gabriel met him. (Bukhari)
B) Providing breakfast for people who are fasting:
The Messenger of Allah, peace be upon him, said: "Whoever provides breakfast for a fasting person, his reward will be equivalent to that of a person who is fasting without decreasing the reward of the latter." (Ahmad & Nissaa'I)
3- Reciting the Holy Qur'an
4- I'tikaf in the Masjed
The fasting person dedicate most of his time in worshiping, praise Allah, reading Qur'an. etc.
5- Umra in Ramadan
The prophet, peace be upon him, said: "Performing Umra in Ramadan is equivalent to Hajj (in reward)." (Bukhari and Muslim). In another report "Umrah in Ramadan is equivalent to Hajj with me."
6- Increase praise of Allah
The days and nights of Ramadan are blessed; therefore, try your best intensify your prayers. Prophet, peace be upon him, said: "Three people will not have their supplications rejected: A fasting person until he break his fast, A just ruler, and oppressed person."