This must be hard
The reason it must be hard is that so few people do it.
"How was your dinner last night?"
Follow up. Not follow up to sell something, just to know. Just to ask. Just to set things right if they were wrong.
The fancy restaurant knows my phone number. Why not have the owner call me the next day just to ask?
The doctor knows my number. Why not call a week later to see how that broken arm is mending?
The accountant knows my number. Why not check in to see if the taxes went out the door okay?
If you really want to generate those referrals, don't ask for a referral, ask if everything was great. Offer to help. Do it in a gentle way, with no strings, no additional addons, no sales pitch. If you really and truly care, why not ask? Not a form, not a survey. Just one caring person, asking. Not that hard, actually.