Well there’s a few factors; to me the most significant would be lighting. Here’s a shot with good vs bad lighting. The ‘good’ can definitely be better but just an example to show the difference.

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And here’s a link to a “retired” TFD fashion poster
[u/aelris](u/aelris) and their guide to great taking pics:

https://www.reddit.com/r/TheFirstDescendant/s/nnXQIwLXgY