How do you thank a man become king?

Raise an army and kill the current king/queen.

Well, royal king like king of Britain would mean that you'd have to be an heir of the current royalty. Or, you could marry the queen or one of her children.

King of random things like rock and roll, or chicken wing eating would be a different story.

If he comes from royal bloodlines, then he could. If his father was king, or mother was queen, then he could.

Or, an uncle or aunt abdicating the throne and he's next in line.

Or, if there was a coup in his country, and he was named to the position because he was high enough born on the winning side.

Play the guitar and sing,it worked for Elvis.