wear that which pertaineth

The woman shall not wear that which pertaineth unto a man, neither shall a man put on a woman's garment: for all that do so are abomination unto the LORD thy God. Deut 22:5

Men and women should dress modestly and in such a way as they maintain their distinction as a man or women.   

Modesty is more about showing love and compassion for others not wanting to tempt them to sin.  It also shows that you value and appreciate the body that God has given you.

Are there or should there be hard fast rules and measurements?  No need to go beyond what scripture actually says because pertaineth can be determined by "we know it when we see it".  

Men can wear a kilt, but not a women's dress.  Men can wear jeans, but men wearing women's skinny jeans with bling is just so wrong (cring).

Women can wear dresses, slacks, jeans, etc that maintain and compliment their appearance as a woman.

Folks dress the way they do either out of a motivation of love of God and putting others ahead of themselves, or a motivation of rebellion and self-centeredness.