Artemis Verailles, Roman copy of a 4th century original (attributed to Leochares).
The first, and easiest to recognize, is Artemis as the hunter. You'll easily recognize this type by the short skirt (she is one of few goddesses that ever wear a short skirt), bow and arrows and she's frequently accompanied by a stag.
Artemis from ca 100 BC, dressed in a chiton, peplos and himation.
Bronze from the 4th century BC.
The other type is Artemis as a maiden, as she can be found in e.g. Brauron. Here she's dressed in a long dress, but still with the arrows.