How to become a king:
1. Have God send someone to anoint you with oil as king
or 2. Be the firstborn male heir (oldest son) of a king
or 3. Be the living child or relative of a king (or sole Queen) who
chooses you to succeed him. There are other ways to become a king too.
Anointing vs crowning:
The first biblical kings of God's people Israel were dabbed with oil
to proclaim they were a king. Crowning as a sole symbol of succession
did not come until much later in history. Though the kings did wear
crowns as symbols of their office/power.
1Sa 15:1 And Samuel said to Saul, "The LORD sent me to anoint
you king over his people Israel; now therefore hearken to the words
of the LORD.
1Sa 16:13 Then Samuel took the horn of oil, and anointed him in the
midst of his brothers; and the Spirit of the LORD came mightily upon
David from that day forward. And Samuel rose up, and went to Ramah.
Kings in biblical times did wear crowns.
2Sa 12:30 And he took the crown of their king from his head; the weight
of it was a talent of gold, and in it was a precious stone; and it was
placed on David's head. And he brought forth the spoil of the city,
a very great amount.
Sgs 3:11 Go forth, O daughters of Zion, and behold King Solomon, with
the crown with which his mother crowned him on the day of his wedding,
on the day of the gladness of his heart.
Here we have both crowning and anointing:
2Ch 23:11 Then he brought out the king's son, and put the crown upon
him, and gave him the testimony; and they proclaimed him king, and Jehoi'ada
and his sons anointed him, and they said, "Long live the king."
See also our "anointing a king" activity.