How should Christians care for their bodies, which the Bible calls temples of God, without idolizing them or investing too much in outer beauty?

Scripture speaks of the Father judging the world, the Son judging the world, and sometimes even the word of Christ judging the world. So, in the end, who will judge?

How do I follow God’s lead in my daily decisions? I know he’s my shepherd, and that he’s leading me, but how do I know if I am following him?