Do you have any reason to believe that they have the money to pay the judgment? If so, you can contact an attorney and have a receiver appointed, who can seize bank accounts. IF the defendant has money, it can be very effective. You will pay the attorney an hourly rate, and the receiver will take a percentage of the judgment. The good news is that both of these costs can be collected in addition to the underlying judgment. If the tenant has assets that you believe can be easily seized, this is a good route.
In most cases, however, tenants do not have any assets to seize. Not too many people renting are sitting on tens of thousands of dollars in the bank. Some are, most aren't. If you do not think the tenant has cash on hand to cover the judgment, you are likely better off turning it over to a collections agency. It will probably not be quick, and they will take a percentage of what they collect, but you won't be throwing good money after bad.