72:15 Each week on Friday, a person should review the week's deeds and resolve to correct any mistakes he may have made. Friday is the day to reflect upon and improve upon the preceding week the same way that the day before Rosh Chodesh is the time to do so for the preceding month.
72:16 One should try to have nice clothes and a beautiful tallis in honor of Shabbos. Isaiah 58:13 tells us to honor Shabbos, which the Talmud tells us (Shabbos 113a) means by wearing clothes that are different from one's weekday clothes. Even if one is traveling with non-Jews (who, obviously, do not observe Shabbos), one should wear his Shabbos clothes. This is because the clothing is not meant to honor other people, it's to honor Shabbos.