It's pretty straight-forward, Drow scowl in disgust, Elves have an aloof sneer.
Originally Posted by Sozz
IAs for proportions, Drow should be what Elves would look like if they became underdwellers, so shorter, and perhaps even more wan. With that in mind Drow should be about Human height, but more wiry. And with D&D Elves being already the same height or shorter than Humans, Drow should be shorter than Humans. I think the way I've usually thought about it, humans look life they evolved from primates, while Elves look like they were created to be beautiful, so much so that they become inhumanly beautiful. Like if you asked someone to draw a person but gave them a description of only the most attractive traits, it would look off.
Canon sources go back and forth on this, but there's at least one instance of drow being described as more attractive than ordinary elves, so...there's that.
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Anyhow, here are two more official examples of elves that appear elfin; the source is Dragonlance, but there's virtually no difference between their elves and those of the Realms.