A proper apostrophes should look more or less like a superscript comma. See Quotes and Accents and Smart Quotes for Smart People for how to get them right.
See also straight quotes, rotated / flipped apostrophes, apostrophes.
Contributed by Peiran Tan
Contributed by Best Studio
Contributed by Quentin Schmerber
Contributed by Matthijs Sluiter
Contributed by Lewis McGuffie
Contributed by Love Lagerkvist
Contributed by Patch Hofweber
Contributed by Stephen Coles