The most important mitzvah for a woman is none other than modesty. When the Torah describes the women in the Tanach, it mentions them in terms of modesty. Sarah Imenu is quoted by Avraham to be "in the house" when he was approached by the angels. Rachel Imenu was traveling "within" her flock so that the view of her is blocked by the flock. Leah, on the other hand, was more outward, as she sits on the crossroads to cry about her fate with Esav, and she bore a daughter, Deena, who also inherited her genes of going out among and got kidnapped by Shechem. So on and so forth.
There are several shiurim about modesty online. LearnTorah.com has several about modesty. Rabbi Yosef Mizrachi also has a few about modesty. I have also written previously about modesty. The confrontations between the Charedim and Dati Leumi folks in Eretz HaKadosh regarding the last Orot Banot school is all about modesty. When Jewish women lack modesty, we have nothing left that differentiates us between us and them, the nations.
