Over the years, I've run into a few things that weren't immediately-obvious to me.
One of the big ones was eating pomegranates by opening them underwater. For those not familiar, pomegranates have a lot of red seeds and white husk between them:
Cutting a pomegranate or even opening a pomegranate tends to burst at least some seeds. The seeds are sticky and stain and tend to spray juice when pierced.
However, if you just cut through the outer hull of the fruit, then open it by hand underwater in a bowl of water, any juice that would have sprayed out is just grabbed by the water. Even better, the (inedible) white husk floats, so it self-separates instead of sticking to everything.
Today, I decided to try eating a watermelon with a spoon. In the past, that's tended to also make things spray, so I tried a grapefruit spoon, one with serrations that runs down the side. And that works great -- the spoon is like a knife, can go more-cleanly through the watermelon than a regular spoon, and still lets you scoop up the watermelon.
Any other neat tips that might be unorthodox or that people might not have tried or know about?
If you enjoy eating snack foods with lots of food dye powder (mmmm hot Cheetos), but hate the fact that it stains your fingers, eat them with chopsticks. No mess on your fingers.
If you struggle with your sandwich/burger innards sliding out of the bread/bun when you take a bite, wrap the innards in lettuce like a taco; place in between the bread/buns with the bottom of the "taco" away from the side you're eating. The lettuce should help keep the sandwich/burger from falling out of the bun.
The chopsticks one was a game changer for me. Helps with mindful eating/portion control, too (until you get good enough with the chopsticks, anyway).
If your burger comes wrapped in paper you should only open one end and peel the paper back as you eat. No mess. Same for souvlaki.
I eat most things with chopsticks, so it's a no-brainer to extend that to snack foods.