Best books which can uplift and reform us are:
1. Quran especially when you recite it or listen to its recitation with pondering. It is very useful to recite or listen to Sura Qaaf which is Sura 50 and Sura Yaseen and Sura Arrahmaan.
2. Saheefa Sajjadiya which has got great supplications narrated from Imam Al-Sajjad (AS) in different situations and for different needs. It is a miracle in its meanings and effect on the heart and mind.
3. Sermon of Ameerul Mo'mineen called Sifat al-Muttaqeen which in Nahjul Balaghah.
4. Jaami' al-Sa'adaat book by al-Naraqi. It is translated and published in English.
5. Mir'aat al-Rashaad by Shaikh Abdullah al-Mamaqaani.
It is very useful for uplifting Sprituality to repeat Istighfaar, Salawaat and Laa Ilaaha Illallah as many times as you can, day and night especially in the Sojood (Prostration).