Eyeball it and hold the camera at arm's length, as if someone else was using it. You can even set it for close-up. The camera will be backwards, but you can still manage to hit a button, right? Try several times until you get a keeper: you can delete the rest.

Aim from above to hide a double chin. Watch out for mirrors or bathroom junk in the background, or fountains spurting water out of the top of your head visually. Only keep the ones with smiles, flattering lighting, good composition and the elimination of too much room/scenery if you want only your face to show up on a teeny profile square!

Got great blue or green eyes? Make sure something else in the photo has that color or a complementary color, and your eyes will stand out. Don't like your head shape or are shy about being online for strangers to see? Crop the photo as needed, and only show what you want to show. Same with bodies: who says you have to show yours to the world? This is about hair or recognition, so many even choose a photo of something symbolic or fun, not a portrait.

Try again until you get that perfect shot! And SMILE!!!!