Once you have a judgment - it is possible to levy against some personal property. However, if they have no job and little in the way of property - you are mostly going to let the judgment sit and accrue interest. The state (if you have them help collect) can suspend drivers license or business licenses. Passport can be kept from being renewed.
Incarceration is also an option if there are repeated orders of contempt for failing to pay support.
The information is for general information purposes only. Nothing stated above should be taken as legal advice for any individual case or situation.