Earn from domain

Domain parking means to park a domain on a parking site. The parking site shall show relevant ads on parked site. Domain owner earns money, when visitors click on ads. To earn from domain, you have to buy domain first. Normally, domain cost from 10 dollar to 30 dollar. Then you have to register on site which park and sell domains. Top domain selling site is sedo. You can park your unused domain on google adsense also.
After perfect registration you have to provide your owned domain which you want to sell. After that, they will show ads on your site with a notice likely 'the site is under sell'. When any visitor visits your site. He shall see ads relevant to your domain and the notice. You shall earn money when any visitor clicks on ads. And persons eager to buy the domain will contact domain parker site. Buyers shall bid to buy your domain.
And, you can sell on highest bid. To earn by selling domain, you have to buy a beautiful, useful, commercial domain. You can park after buying. Or, you can build your site on the domain. After getting popularity, you can park it for selling.