There is a specific disappointment in checking a selfie you just took. The light is fine, the photo is sharp, and yet the face looking back is not quite the one you know from the mirror.
Usually that has nothing to do with your face and nothing to do with editing. It is geometry. A phone held at arm's length sits about a foot and a half from your nose, and portrait photographers do not put a camera that close to anyone on purpose.
Four things account for most of the difference: how far the lens is, how high it sits, which lens you use, and where the light comes from. All four are free, and all four happen before you open a filter.
Distance changes the shape of your face
A lens draws whatever is nearer to it larger. At arm's length your nose is closer to the glass than your ears by maybe five inches out of eighteen, so the nose and forehead come out enlarged and the middle of the face reads wider than it does in a mirror.
Move the camera to three or four feet and that same gap becomes a small fraction of the distance, so features settle into the proportions people see when they talk to you. Nothing about your face changed; the arithmetic did.
Your arm is a fixed length, so there are three ways out: hand the phone over, prop it up and use a timer, or shoot from further back.
Back up, then zoom in
Lean the phone against a book or a mug, step back three or four feet, and zoom in until your head and shoulders fill the frame. You give up a little resolution to the crop and get back the proportions only distance produces. Sweet Selfie keeps a 1x to 3x zoom and the self timer on one screen, so you can set the framing first and then walk into it.
Put the lens slightly above your eyes
Height decides what happens to your jaw and neck. Hold the phone low and the nearest thing to the lens is the underside of your chin, so the jaw and throat widen and the nostrils become a feature. Lift it a few inches above eye level, tilt it down slightly, and the jaw line separates from the neck while the eyes open towards the camera.
Held far overhead the forehead takes over instead, so a few inches above your eye line is the useful range. While you are there, push your chin forward and slightly down. It feels ridiculous and looks normal in the photo, because moving your head away from your neck creates a gap where the jaw used to blur into it.
The ultra wide lens is for rooms, not faces
On iPhones with more than one rear camera, the 0.5x ultra wide exaggerates everything closeness already does badly, and it stretches whatever sits near the edges of the frame, which is where faces land in a group shot. Use it for the room, and keep faces out of the corners.
The 1x main camera is the safe default. If your model has a telephoto, 2x, 3x or 5x depending on the iPhone, that is the flattering one, because it makes you stand further back to fill the frame. The front camera is a fixed wide lens: convenient, but on most iPhones it gathers less light and less detail than the main rear one.
One light, from the side, a little above you
Direction matters more than brightness. Light coming straight at you fills in every shadow, and shadows are what tell a viewer that a face has shape.
Turn so your main light sits roughly forty-five degrees off to one side and a little above your eyes. You get a soft shadow under the nose, another under one cheekbone, and a face that reads as three dimensional. A window does this for nothing; ceiling lights do the opposite, dropping shade into the eye sockets.
Turn your shoulders and let your face settle
Squaring up to the camera presents your body at its widest. Rotate thirty or forty degrees, keep your face turned back towards the lens, and you get a narrower body line and a jaw seen at an angle.
Look just above the lens if you want the eyes wide, or straight into it for directness. Tighten the lower eyelids very slightly, the way you do when you are amused: a fully open eye reads as startled, a narrowed one as relaxed.
Edit in the right order, and stop early
Crop and straighten first, since both change what the rest of the picture is doing. Then set exposure and skin tone. Only after that reach for a filter, and treat it as a mood rather than a repair.
Skin has texture, and once all of it is gone the face stops looking like a photograph of a person. Sweet Selfie's beauty mode leaves that texture in place, and its one-tap studio lighting is worth trying first, since fixing the light often removes the reason you wanted a filter.
Quick answers
Why do I look different in photos than in the mirror?
A mirror shows a flipped version of your face that you have looked at your whole life, so the unflipped photo reads as wrong even though it is what everyone else sees. A phone at arm's length also distorts proportions in a way a mirror never does. iOS has a Mirror Front Camera switch in Settings, Camera.
Should I use the front camera or the rear camera?
The rear main camera on most iPhones gathers more light and holds more detail, and using it forces you to prop the phone up, which fixes the distance problem at the same time. The front camera usually has a small button that widens its frame, and on the newest models it can take a landscape-shaped photo without turning the phone.
Does Portrait mode help with selfies?
It can. A blurred background separates you from a cluttered room, and on iPhones that support it you can adjust the depth effect after the shot. It does not fix angle, distance or light, so treat it as the last step. On the front camera, note that any zoom is a crop of an already small image.
Where to get it
Sweet Selfie: Camera & Editor puts these pieces in one place: a framing grid, a self timer, 1x to 3x zoom, one-tap studio lighting, a beauty mode that keeps skin looking like skin, eight colour filters, nine frames, and export at square, 4:5, 9:16 and 16:9 with no watermark. It is free on the App Store.
Try one photo from four feet away before you take another from eighteen inches.