My daughter once explained HER interpretation of Tznius which I think truly hits the nail on the head.
She said ” Mommy, it is not the length of your skirt or the length of your sleeves or whether your collarbone is covered, or the color of your suit,your stockings or the style of your shaitel. It is an issue of perception.
If you dress in a way that draws attention (from men, and even other women) whether because your clothes are tight, too short, too bright or too striking that is not tzniusdick.
A woman should dress in a manner that is pleasing and balibatish, BUT if she draws attention, THAT is NOT tznius.”
I think she nailed it in one.