Say, “If you love God, then follow me, and God will love you, and will
forgive you your sins.” God is Forgiving and Merciful.
Those who believe, then disbelieve, then believe, then disbelieve,
then increase in disbelief, God will not forgive them, nor will He
guide them to a way.
If you love and follow God, He will forgive you ...
Recite Astaghfirullah constantly. Say it 3 times after every salat and minimum of 100 times a day. It means, "I seek forgiveness from Allah". Allah's Messenger (ﷺ) said, "Whoever says, 'Subhan Allah wa bihamdihi,' 100 times a day, will be forgiven all his sins even if they were as much as the foam of the sea.