It is to abandon sins by leaving them and to distance oneself from major sins. (It means to resolve never to return to those sins again, to restore all injustices one has committed, whether major or minor, to make up for obligatory acts previously missed, to discipline the nafs (the lower self) in acts of obedience, and to weep in the pre-dawn hours.)
The third aspect is that the believers (mu'min) repent from minor sins that arise from error, heedlessness, ignorance, and forgetfulness. (Jāmiʿ, 21)
Tawba (repentance) is to turn from blameworthy acts to praiseworthy acts. Ināba, on the other hand, is to turn not from anything else, but from Allah to Allah Himself... (Jāmiʿ, 54)
The first of the prerequisites of tawba (the acts that should precede repentance) is the awakening of the qalb (the heart) from the sleep of heedlessness; the servant's contemplation of the bad ḥāl (spiritual state) he is in; and listening with the ear of the qalb to what the religion has prohibited. For this reason, the Prophet (peace be upon him) said: "In the qalb of every believer, Allah Most High has placed an admonition."
The second prerequisite is to abandon bad companions. For they hinder tawba by word, deed, and other means. Even if a person breaks and then renews his tawba once or several times, as long as he does not abandon it, he is counted among the fortunate (saʿīd) ones. For such a person hopes to show sabāt (steadfastness) in his tawba. Surely, every promise has a [fulfillment].