According to the Rambam, the main essence of Teshuva is וידוי, confession. The ability to verbally admit one’s own shortcomings, is critical towards true repentance.
Yom Kippur has a total of ten וידוי’s throughout the day. We say the first confession already at Mincha before the fast even begins. We are to be focused during our prayers on how we can improve and correct our negative character traits.
The Rambam comments on this as well. He says that changing bad habits is sometimes more difficult than trying to repent for actual transgressions.
Everything is related. When we speak of Viduy, it represents our courage to openly acknowledge that we are not perfect and there are things about ourselves that we can improve on.
We should use Yom Kippur as a serious day of soul searching that should end with the resolve that this coming year, we will work on ourselves in sincerely coming closer to Hashem by becoming better people.
גמר חתימה טובה