Check your state's laws about filing a mechanic's lien. In CA, there's very strict statutory notice required, and these liens aren't self=executing, meaning you still need to file a lawsuit to collect.
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File a mechanic's lien at your local county recorder's office.
Another option would be to contact an attorney and have the attorney send a formal payment demand.
Finally, if the amount to be paid for your services was less than $3,000, you can file against the person in your local small claims court.
Disclaimer: This does not constitute legal advice. No attorney-client relationship has been formed through this answer.
Mr. Sauter offers excellent, concise advice. After you have filed your lien, it may be useful to pay an attorney to send a collection letter and see if it prompts the person to pay. Good luck.