1 Don’t pose too much. The more natural you look, the better the photo and the more chance you’ll have of looking best. See this also http://www.emilyexon.com/blog/weddings/engaged-wedding-show-really-must-attend/
2 Stand straight with your head held high. Turn your body slightly to the side by putting one leg in front of the other. This allows you to show your face and body in a semi-profile, which is very flattering.
3 Smile: Nobody looks good when they are miserable. You’ve probably been told to say “cheese”, but this can often make a smile look like a grimace. For a natural, gentle smile that is easy to maintain, push your tongue against the back of your top teeth. Don’t just smile with your mouth, smile with your eyes too.
4 Open your eyes wide (not too wide or else you’ll look startled or slightly crazy). Don’t stare directly at the camera, as this may result in your eyes looking red in the photo.
5 Direct your gaze at a spot right above the camera. Imagine you are looking at a friend to give yourself a friendly expression in the photo.
6 Relax as much as you can. Just before the photo is taken, take a deep breath and let it out. Don’t hunch, shake your limbs loose a little so you don’t look stiff.
7 Quickly glance in a mirror before the photo is taken if you get the chance. Make sure your hair is how you like it and there’s nothing stuck in your teeth.
8 Listen to the photographer if she or he is a professional. Often the photos you want to look best in are those taken of formal occasions such as proms, weddings, 16 Birthday Parties, etc. Take notice of what the photographer says, they want everyone in a shot to look best so do as you are told. If you want to look best in a photo where you are not the main subject, do as the photographer tells the bride, birthday boy or whoever is the main subject so that you look best, not them, if you want.
9 Practice posing and expressions in front of a mirror and by taking selfies. Perfect your best smile and be ready to give it whenever you are being photographed. Try posing and taking selfies in different light conditions so you know how to look best in sunlight, dim light etc.
10 Dress well at all times. Be ready to look best in photos by always being best dressed. It might be easier for you to look best in a flattering shirt and nice pants and shoes if everyone else is wearing tee-shirts, jeans and sneakers.