What I look for are the nose and the tail...A big mature doe will have a long nose...Also with a smaller deer the tail looks long in relationship to its body, it will usually be longer than the hams on the deer...Here in NC our bowseason opens on September 9th...in the Piedmont area it runs about 2 months...I like to take does from early bow season until the first or second week of October...Then the bucks are starting to rut and I buck hunt....I start back taking does in the middle of December as the rut cools down...During the later part of the season you have to really pay attention and compair deer if possible...Its easy to kill a larger button buck at this time, eapecially if you see them under low light conditions, as another said especially if they come in by themselves...A good set of binoculars also helps...Good Luck