I see a goofy looking subject, holding a phone high, positioning it on a down angle... probably making pursed lips or some sort of goofy face, flashing a peace sign or other hand-gesture. This "pose" may seem cliche, but we can learn something from the "classic selfie" that many of us joke about.
it TIGHTENS: Looking up stretches and pulls the skin around your neck, chin, and face. It's like an instant neck lift that helps define the jaw and lengthen the neck, giving space between your face and body.
it HIDES: Shooting a selfie on a down angle hides things. In looking up and tightening the skin, we reduce or eliminate the double chin (which lets face it, we all have a double chin). A down angle also puts your face first, and your face being the largest focus in the photo will overlay and minimize your body.
it LIGHTS: Looking up brings your face into the light, and better light makes better photos.
TIGHTENING is all about good posture and/or twisting. You can turn your head and body separate of each other, whether you are looking up, forward, or down. And bonus - ANGLES are our friend not just because they HIDE through tightening, but angles are super flattering and add dimension to your figure!! Finally, you can find great light anywhere, you just need to know how to find beautiful light.
Perspective is a big factor in flattering portraits. See the giphy to the right? This is a play on perspective... place your camera too closely to your face or body, and certain parts are bigger or smaller than they should be. See how big her nose is? And how her face falls off too much? But then as we back off to a more flattering perspective, her features are proportionate.
When taking a selfie, it's hard to get the camera more than 3 feet away - we're limited by the length of our arms, or if we are lucky, a selfie stick. Sometimes you will find, it's better to hand the camera to a trusted friend to take the photo.
Cell phone cameras are made for a wide angle, so it's not just about stepping back further, but about zooming in!
Shooting downward is not always best. Downward angles can definitely be flattering for seated positions, but shooting down on a subject shortens the figure. Downward angles can eliminate length, which is not flattering, especially if the subject is standing.
When shooting portraits, you'll often see me positioned just below eye level for seated subjects, and squatting to about stomach or waist level for standing subjects. This gives an even perspective of the figure, while also enhancing the length of the subject, making them look taller and leaner.
Think about the feeling your angle will convey as well.. Photographing at your subject's eye level creates a more intimate photo - you feel more connected, while looking up at a subject can make them appear more powerful.
Finally, I think that selfies teach us not to ignore our background. We've all seen OK-looking selfies that have either ugly backgrounds or revealing (aka: embarrassing) objects in the background. So, your angles and perspectives can allow you to move around and change it.