If you're having a hard time faking a smile, or want to get the best out of a photo you're taking, ditch the "cheese" and try "cheeks" instead.
Photo by cheriejoyful
There are a lot of elements involved when it comes to natural looking expressions, but smiling is a tool we all have and should use more often. To make your smile more genuine looking — and feeling — Richard Stephens at The Guardian recommends a simple word substitution:
Next time you're having your photograph taken don't say "cheese", say "cheeks". Saying "cheeks" will not only shape your mouth nicely but will also remind you to squeeze your cheeks upwards into a visually satisfying, genuine-looking Duchenne smile.
The "k" sound at the end of word is what begins to lift your cheeks upward, and that's one of the most important aspects of a natural-looking smile. If you're in a situation where saying the word "cheeks" for no reason might draw unneeded attention, you can just mouth it. This can be especially effective when you're taking photos of kids. There are other ways to get those cheeks up too. Words that end in "uh" are effective as well. So smile and sell it.
How we grin and bear it - the science of smiling [The Guardian]