The key is picking something topical, getting like-minded people to join you and making it look authentic.
These five girls managed to pull off the trifecta.
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They dressed up as the Final Five — the US Women's gymnastics team that won gold in Rio over the summer. And while anybody can dress the part, it's pretty darn cool when Simone Biles (who won 4 gold medals in Rio) shows up on your Instagram feed and cosigns it.