Hadhrat Thanavi (may Allah have mercy on him) said;

“The real treatment of thinking ill of others (Badgumani), undue curiosity (Tajassus), and Gheebat (backbiting) is to adopt Tawazu’ (humility) and remove Takabbur (arrogance, grandiosity) from one’s heart. But until one gets rid of these core spiritual illnesses, until such time he should treat his illness of Gheebat in the following way; (1) reflect and ponder before you say anything, (2) fix some fine on yourself if you do slip up (and commit Gheebat), and (3) divert your attention towards Allah Ta’ala’s Dhikr (remembrance) when you get bad thoughts about others.”