If you are having a lot of domain names for sell and dont know what to do with them until its not selling, there is a trick through which you can earn money easily.
Trick is Domain Parking.
WHAT IS DOMAIN PARKING
Domain parking is the way to earn money online.If you are having lot of domains free then you can park your domain with many parking companies.
So whenever a visitor come to your site then he or she click the ads then you gets the money for clicking. Then you get paid according the policy of different market palaces.
DOMAIN PARKING COMPANIES
HOW TO PARK DOMAINS
You just need to list your domains in the parking companies and they will provide the option for parking then you need to shift your domain name servers according to the parking companies.
It takes time to shit the NameServers and then ads are automatically put on your parked page by these companies.
HOW TO SELECT GOOD DOMAIN NAME FOR PARKING
This is the major thing in this process we cant ignore it.
The domain name your selecting for parking should get good Organic Traffic.
So first thing keep in mind that your domain name should have good organic traffic.So maximum number of visitor come to your parked pages and then click on it so that you can earn money easily.
HOW TO INCREASE PARKING REVENUE
The whole phenomenon is on the how to increase parking revenue?
There are two ways to increase parking revenue ,
Layout Changing
Keywords Changing
OTHER BENEFITS
These companies list your domain name that means on your parking page it shows that this domain is for sell and contact us.So you can sell your domain names too.
So listing and parking these are the two benefits of a free domain name. 
