I place the ad. I don't give my phone number. I have them reply to ad via email with a resume or qualifications and other information I ask for.
I then weed through the resumes, there are several things that I look for that make me immediately respond with my canned response..... "Thank you but....blah, blah, should anything change we will be in touch".
Then I send emails to the remaining applicants, giving them each a specific time to call. Not too early, not to late but specific. If you do not call within a few minutes of that specific time, you are out.
If you do call at the given time, and you pass my phone interview, I will set up a time to meet in person.
If you are late for interview, you do not have the job. If you are dressed like a bum, you don't get the job.
I then just talk to the potential employee, very casusal conversation but specifically designed to get the information needed to determine the next step.
Should all things go well, we will do a one week training/evaluation period with my field supervisor, then an additional week with one of my techs.
The feedback they give me is the major factor in determining if this becomes a full time employee.