How do you make a claiming system?

I wanna make a claiming system for a plugin i'm making, i don't wanna use any other plugins.

 

1. Decide on how a player will claim the region (clicking blocks? Standing on the block and typing a command? Standing in an area to claim 100 blocks in all directions?)
2. Check that the region they've chosen doesn't overlap any other region or isn't too large.
3. On the breakblockevent, check that the block is in the players claimed zone(s).
4. Remove all other types of destruction like lava, fire, tnt, creepers, and the likes.

What also might be cool is if someone has good building skill, an admin can give them the ability to grant other players more building space if they like what the other player has built. But that could be subject to abuse so it would need testing...