The best way of seeking Allah's forgiveness...

Istighfar is the key to success.

Allah Akabr

It’s part of the morning and evening adhkar. Every Muslim should memorise this dua. You can download various apps that have it, as well as audio from different reciters to your phone. Play it in the morning and evening; you can also get a hard copy of the "Hisnul Muslim" book.

God will forgive your sins even if you kill, rape, pedophile kids that's why holy land in the Middle East still at war.