Catching them getting into or out of their car when it's been followed to shopping center parking lot can work.
I got someone served by having a flower delivery made to the front desk of a medical clinic, in May of this year.. Inside the bouquet, delivered by a young woman I had hired for this purpose, we had rolled up inside of a waterproof plastic stapled tube, the summons, and then crammed it down the middle of the bouquet where it was invisible.
It worked perfect. Be sure right afterward, to have the process server sign the court document in duplicate called the "Proof of Service" then file the original and have the second one "endorsed" by the court and returned to you.
A process server told me that another thing that usually worked was to have someone dressed as a Pizza delivery guy come to the business, and ask for the person at the front desk.
The person would always come, for the "Pizza" but sometimes say he didn't order the Pizza.
The process server would say, "Well, you ARE John Doe, aren't you?"
The person would say, "Yeah, but..." and the process server would thrust the box at them, and say "Here you go."
Then the person would open the box, and the service of process was inside and no pizza was there.
But it was too late, he just got served.
Worked every time,
Another one that worked but is really mean, was to phone them at work or at home and say they are the local Hospital calling, and that their spouse just got horribly injured and was in the ER and you have to come there right away.
Nailed them with service when they raced into the Hospital ER parking lot, hit them with papers, at the moment they jumped wild eyed out of the car.
Always worked.