رَبَّنَا وَسِعْتَ كُلَّ شَيْءٍ رَّحْمَةً وَعِلْمًا فَاغْفِرْ لِلَّذِينَ تَابُوا وَاتَّبَعُوا سَبِيلَكَ وَقِهِمْ عَذَابَ الْجَحِيمِ
Translation
Our Lord, You have encompassed all things in mercy and knowledge, so forgive those who have repented and followed Your way and protect them from the punishment of Hellfire.
Astaghfirullah is a short, powerful prayer from the Quran. The Prophet said it over 100 times daily. It means I ask my Lord Allah to forgive me and I turn back to Him.
Say astaghfirullah with your heart. Promise Allah you will stop doing the sin. If you hurt someone, say sorry to them too. This is tawbah.
Say A`ūdhu bikalimāti-llāhit-tāmmāti min sharri mā khalaq three times in the evening. It asks Allah to protect you from every bad thing.
Feel bad about the sin. Say astaghfirullah with a true heart. Promise not to do it again. Do good deeds and fix any harm you caused.
The Prophet taught this for Laylatul-Qadr: Allahumma innaka 'afuwwun tuhibbul-'afwa, fa'fu 'anni. Say it with a true heart to clean big sins.
Dua Against Temptation (Surah Yusuf)
Dua to Be Safe on Judgment Day - Surah Ash-Shu'ara
Prophet Yunus Dua for Hard Times (From Surah Al-Anbiya)
Surah Fatiha - Ask for Help and the Right Path
Ask Allah to Save You from Hellfire (Surah Furqan)
Ask Allah to Accept Your Good Actions (Surah Al-Baqarah)