Similar as in any other time of the year, by repenting sincerely, stopping the sin at once, giving back what is not yours or correcting your mistake towards others (and apologizing and asking them for forgiveness) and trying never to repeat it again.
To seek forgiveness one doesn't need to recite qur'an nor to seek a special hour. Nevertheless it may be ...
All of us are sinful and incomplete. Our job is to stay away from sins as much as possible and ask for fogiveness always.
In Quran Allah mentioned many prayers of HIS messengers so we can repeat them as per our situation
Best time of pray is last part of night