Actors, stand up comics and public presenters practice expressions and poses in front of mirrors all the time. Why? So they know what they look like when they are making a face or gesture.

That theory can be applied to photography. If you know how it feels to make an expression/pose you’re happy with, you can do it again and again. Make an expression you’d be happy to see in a photo, remember how it feels to make that face. Try making that face looking away from the mirror and, still keeping that, look at the mirror to see if you got the desired result. Rinse. Repeat.