Rajab- Spiritual cleansing.
1) Fasting: It is highly recommended to fast in this month of Rajab even for one day at least. A hadith says: Whosoever fasts a day in Rajab, the fire of hell will be away from him a distance of one year's journey, and whosoever fasts 3 days in Rajab, will be entitled for Paradise. Imam Ali (as) used to fast the whole month of Rajab.
2) Seeking Forgiveness (Al-Istighfaar, Istighfar): The Holy Prophet Muhammad (saw) used to say: Rajab is a month of seeking forgiveness, so seek forgiveness from Allah (SWT); He is verily the Forgiver, the Merciful. It is highly recommended to repeat 'Astaghfirullaah wa as-aluhut tawbah'
3) Sadaqa and Charity: There is a big reward for Sadaqa and charity in the month of Rajab. Those who cannot fast may give Sadaqa to the poor every day, or recite 'Subhana Ilalahil Jaleele Subhana Man la Yanbaghil Tasbeeho Illa Lahoo; Subhanal A'azzinil Akrame; Subhana Man Labisal Izza wa Howa Lahoo Ahlun.'
4) Repeating 'Laa ilaaha illa-Allah' 1000 times.
5) Repeating 'Astaghfirullaaha zul jalale wal Ikraam min jamee al zonoobe wal aathaam' 1000 times.
6) Repeating Sura Al Tawheed 'Qul-ho-wallaho Ahad' or Surah Al-Ikhlas 1000 times to get the reward of 1000 Angels and blessings on the reciter, his / her children, family and neighbours.
7) It is recommended to recite Sura Al Tawheed 'Qul-ho-wallaho Ahad' or Surah Al-Ikhlas 100 times every Friday in the month of Rajab.