Re: proof of service
Methods of service of process are covered in the Code of Civil Procedure, and all references to sections refer to that Code, which you can access via the Internet or at most libraries.
There are two basic methods of serving an adult individual: personal service (section 415.10) and service by mail (section 415.30). Note that mail service requires that the person served send back a signed acknowledgment form, but if the person fails to send it back, he is liable for the additional costs you incur in serving him by another method (section 415.30(d)).
If neither a 415.10 personal service nor a 415.30 mail-and-acknowledgment works after using "reasonable diligence," you can use section 415.20(b), which authorizes leaving the papers with someone else at the home or place of business, followed up by mailing.
Finally, the court can authorize service by publication; see section 415.50.
If your case is eligible for service, filing and recording of a lis pendens (notice of pendency of action), your attorney should do this soon after the complaint is filed.
Your question suggests that you aren't represented by counsel; most attorneys would know how to get the service accomplished. If you aren't represented, you should be; this kind of case really requires expertise. Further, it's much easier for an attorney to file a lis pendens, in pro. per. plaintiffs need prior approval from a judge. I recently handled a similar case (removing a person who showed on title as a co-owner) with success, and would be pleased to take a detailed look at your case, gratis, if you are currently unrepresented.
By the way, four attempts at service should satisfy the reasonable diligence requirement of section 415.20(b).