Avoid being photographed from below
Being photographed from below can be extremely unflattering, just ask Thalassa Boom Resortwear. "Instead of having your photo taken from below, get the person snapping away to take a photo from above, with you looking up towards the lens. This creates a magical optical illusion, making your body, face and neck thinner!"
Avoid full frontal shots
Put your arms on your hips
Stick your chin out
This Lifehacker article explains that tilting your jaw forward can make your face look thinner and get rid of the dreaded double chin. The last thing you want from your holiday photos are multiple chins!