depends on a few external factors you probably already know of but play more of a major role than you realize: camera lens, lighting, and angle.
regarding camera lens: they distort facial proportions in sometimes extreme or subtle ways. this is why you might like how you look in a mirror but in a picture:
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lighting does the same thing. minus harsh shadows, accent lights will do you either dirty or better, as it would highlight or hide certain parts of your face. simple lighting differences:
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regarding lighting: something i was told from a photographer was to take selfies with the light behind you, not with you facing the light. it made my face look less detailed n gross w/o having to use so many filters. obviously don’t do this if the shadows are mega harsh.
regarding angles: consider the camera lens and just shift your weight depending on what you want more or less visible. i have a double chin cuz im a fatass, so i lean my head forward just enough that it’s not the first thing people see. it depends on tons of factors and what the intent of the photo is but yuh.
expressions also very heavily play into it— sometimes that’s more difficult to give universal advice on. i have a wide ass smile. im the joker babyyy kinda smile. i learned to put more pressure on my upper lip and to not do a “full” smile. it looks better in most contexts. etc etc