There are four major components to teshuva with a lot of corresponding facets. So, we’ll list the four here first outright and shed some light on why they matter if you truly want to achieve teshuva and draw close to G-d again, and we’ll then spell out each component’s facets in the next chapter.
In order to achieve teshuva you’d first need to fully regret having committed the sin; second, to stop doing it; third, to admit to having committed it and ask to be forgiven; and fourth, to wholeheartedly take it upon yourself never to commit it again. Let’s explore each a bit.
Your regretting having sinned (component 1) shows that you’re now discomfited and embarrassed by something that you once unthinkingly assumed was all right which you now know was wrong. That’s a hard thing to do: only someone who has given thought to his or her actions and motivations can manage to do this, so you’re to be commended for it by all means.
When you stop committing a particular sin (component 2) that shows that you now reject and repudiate it, and consider the very thing that you’d once valued as being sorry and odious instead. That also indicates maturity, as well as a growing affinity with G-d’s values. But it likewise shows that you’ve to come realize that your actions have their consequences, and that they truly do affect your relationship with Him.
Admitting a sin and asking to be forgiven for it (component 3) shows that you’ve come to humbly acquiesce your will to G-d’s own, which itself indicates a deepening of your commitment to Him and your realizing how important He is in your life.
Finally, your wholeheartedly taking it upon yourself never to commit that sin again (component 4) is a sign that you realize just how wrong and serious the sin you committed actually was, which indicates that the fragility of your relationship to G-d has truly dawned on you.
And since we see all the time that when someone who has wronged another person shows that he truly regrets what he did, admits to it, and takes it upon himself never to do it again, that that’s reason enough for the other person to forgive him, we’re sure (and assured) that G-d forgives us for our wrongdoings when we do those things, too.