Causes of Increase in Imaan
1. Praying to your Lord, Glorified and Exalted, in secret, supplicating a lot to Him, hoping in His reward, and engaging in much remembrance of Him.
2. Contemplating His Book, for nothing helps the recovery of the heart except the Book of Allah Mighty and Sublime. There are many youth who busy themselves even with sciences of the Shari`ah at the expense of reciting the Qur'an until their hearts eventually harden. So if this happens with acts of obedience, what about one who occupies his heart with sins?
3. Regularly performing your obligatory prayers in congregation, for Allah guaranteed the one who guards his obligatory prayers in congregation that he will neither abandon him, nor humiliate him, and that He will guard him in this world and the next.
4. Regularly performing as-sunan ar-rawatib (acts of Sunnah that were stressed and regularly performed by the Prophet, sallallahu `alayhi wa sallam), and doing plenty of them, for whenever you prostrate to Allah with a prostration, He raises your level.
5. Accompanying and loving the righteous. "The person is with one he loves." [Al-Bukhari] "Do not befriend except a believer, and let no one eat your food except a taqiyy (a pious, God-fearing person)." [Hasan, related by Ahmad, At-Tayalisi, Abu Dawud, At-Tirmidhi and others]
6. Knowing that Allah, al-Wahid, al-Ahad, watches over us, and knowing that He is with you: "Does He who created not know, while He is the Subtle, the Acquainted?" [al-Mulk (67):14]
Knowing also that He knows what you hide and what you make apparent: "Have you not considered that Allah knows what is in the heavens and what is on the earth? There is no private conversation of three but that He is the fourth of them, nor are there five but that He is the sixth of them - and no less than that and no more except that He is with them [in knowledge] wherever they are. Then He will inform them of what they did, on the Day of Resurrection. Indeed Allah is, of all things, Knowing." [Al-Mujadilah (58):7]
Our Shortcomings in the World of Imaan
1. Taking oneself to account as the Salaf used to do; they used take themselves to account in detail prior to sleep: What did we put forth from good so that we thank Allah? What did we do from evil so that we repent to Allah?
2. Seeking guidance and advice from the people of knowledge and callers to Allah.
3. Visiting graves, for it is a means of remembrance of the hereafter, and it guides a slave to the Straight Path.
4. Reading biographies of the Salaf. Exemplary biographies are those lived by the Sahaba, at-Tabi`een and imams, such as Ahmad, ash-Shai`i, Malik, ath-Thawri, al-Awza`i and many others.
5. Praying upon Allah in secret and supplicating to Him in the last third of the night.