I figure, "so what?" Maybe they gawk because they're wishing they were you. Ever think of that?
Really--maybe they're thinking that if they were solo they wouldn't have to deal with the relationship stuff that defies logic, like "Honey, I know you really like the local wine and you hate sugary soft drinks...but I feel like a Coke and I can never finish a whole one...so would you do me a big, big favor and promise to drink half so I can feel free to order one?"
Solo dining is really just a matter of changing your mindset--and enjoying your meal. Here are some ways to do that.
They wanna gawk--give 'em something to gawk at! Dress to the nines; wear a big floppy hat, or wrap a Victorian Cravat around your neck.
Make them think you're somebody special. Because you are:
"Fine dining is a bit of theater, and solo diners, by our singularity, are the stars. So enjoy the chance to be really special. Fantisize if you wish." Lea Lane in Solo Traveler - (review)
Scribble in a notepad. That's right, most "experts" recommend you read a book. Balderdash. I say you might as well write one. It's more lucrative.
To me, reading in a restaurant seems downright rude. I mean, here you are in a joint that the owner is proud to have furnished in a tasteful manner and you're spending dinner time trying to immerse yourself in someone else's written fantasy world. How gauche. Besides, nothing says, "Now there's a pathetic loner!" more succinctly than the sight of a waiter cycling through a number of slapstick routines trying to slip a plate of steaming penne alla puttanesca under the vapid pulp fiction of an oblivious reader.
Besides, if you take out your little pad and pencil, they can't be sure you're not a reviewer. This can pay dividends. Engage the waiter; ask about the origins of that blue-green sauce ladled over your chop like an oozing fungus. Maybe you'll get invited to the kitchen. What you do there is up to you, but it could be quite an adventure, eh?
If you don't know what to write, doodle. What's wrong with folks thinking you're an artist?
Remember: The restaurant's your stage. Make them envy you.
Go to places conducive to interacting with folks and food. Tapas bars in Spain are perfect for people who want to nibble hot food while trolling for human contact. In Italy, lots of 20-30 year old men eat out solo at places that offer "workers meals" at reasonable prices, often returning to the same place every night. You won't be alone in your aloneness with these guys.
And finally: don't accept a table near the kitchen door or anywhere you can smell the urinal cakes.
You're worth a fight for a good table, but you don't need me to tell you that.