@Steven May I've only done one campaign of direct mail so take my comment as one who is only slightly experienced. I was able to land a 4plex using seller financing here in red-hot Las Vegas, NV.
My mailer was hand written and was very simple:
"
Hey Steven,
My name is Spencer Cornelia and I am interested in buying your property at 123 Candy Lane. How much do you think it is worth?
Text/Call -- {Phone Number stamp}
Email -- {Email stamp}
Spencer
"
In a couple months, I'm going to start another direct mail campaign and will be using services instead of hand writing. Hand writing is great and more authentic, but you're so limited with how many you can send out. Sadly, the hit rate is super low so only sending out 40 has a very low probability of success. I don't want that to stop you from doing this, but once you go through 2-3 rounds of hand writing mailers, you'll quickly find that spending $1k-$2k on 1,000's of mailers is probably a better use of time.
But you asked for advice...
Don't worry about overthinking it man. If the people have any interest in selling, they'll call. I know Patricia above says she receives mailers all the time, but I don't think that's the case for most owners. I have a feeling most of these owners will see your cute message and will call if they want to sell.
A simple message is probably all that's needed.
If you want some real advice...
Check out Sean Terry's Flip 2 Freedom podcast. Dude is all value. "All steak and no sizzle" kind of guy. His recent podcast on wholesaling (of which he has plenty) really helps lay out how to do well with marketing and grabbing off market properties.