Refer any slaves you have to the site and get them to sign up, make sure that they put your username as the referral in the referral box on the join page.

Then make sure they verify their profile.

The Master with the most number of referred and verified slaves after a week will get featured for a month for free and also 25% of the total number of credits bought by their slaves when they verify.

This is a great offer and a good way of getting credits for free!