Chastity is a stewardship principle - the stewardship of young men's hearts. Just as a young man in a dating relationship should respectfully and carefully take care of the young lady's emotions that she entrusts to him, a young woman should likewise take care of a young man's passions and not purposely tempt him with revealing clothing, body language, or words.
Dating is stewardship, plain and simple. You are a steward of each other's hearts and passions, and you are caring for them out of respect for each other's future spouses (even if they turn out to be someone other than you).
People in society today think that if a guy leers at a girl, he needs to control himself better - that he is entirely at fault, no matter what she is wearing - that girls can wear whatever they want and the guys must deal with reigning themselves in. Now, I am not saying that a man shouldn't control himself or am excusing improper behavior on the part of the men, but shouldn't women also bear some of that burden? When your neckline is cut so low that your cleavage plunges lower than your breasts, what are you really saying to men? What are you saying about yourself? What are you really asking for? And what... really... do you expect to be the response from young men?
The bottom line: if you don't want to be pursued just for your body, if you are serious about being respected for your intellect and emotions, if you value love over lust, then dress likewise. Choose clothes that are stylish, but not overtly sexy. Respect yourself and your brothers with what you wear and how you act.