I see there were kings. How does one become a monarch of any land? 

You gain popularity. Then you use that popularity to force hands to gain a position.

If possible make it look like you had no hand in it and everyone demanded for it.

Although popular vote is by far the most common method to become a monarch, other methods are possible, such as becoming part of a bloodline or royal family. Particular game-masters have also become monarchs through design and development of particular domains, notably, Mur of the East and arguably Dark Demon of the Labyrinth.

In all cases, it is important to note that acknowledgment of the role is usually more important than the role itself; as a wise being once did say: 
"He who must say 'I am the king' were not, indeed, the king."