If someone owes you at least $500 in a commercial context, and if you are concerned that the debtor may try to dispose of the assets before a judgment, you may be able to file a lien on the debtor's assets before a trial and a judgment. California law allows a creditor to obtain a prejudgment writ of attachment on a debtor's property in certain cases, after posting of a bond.  A creditor, who has followed the statutory requirements, may, in some cases, be allowed to record a lien against the real and personal property of a debtor before the case goes to trial, in order to preserve the property and to prevent the debtor from disposing of the assets before the trial.  
The claim has to be commercial in nature, for a fixed or readily ascertainable amount of money, based on a contract and at least $500.  Further the claim has to be unsecured. If the debtor has sued a third party in a separate action, the creditor may obtain an attachment lien on that action and to any judgment obtained by the debtor in the separate action.  This is a powerful remedy, which, if used properly, can help preserve the debtor's assets until trial and a final judgment.