Many approaches can be taken when talking about the subject of modesty and God’s will in this regard. We could use 1 Timothy 2:9 or 1 Peter 3:3-4 to talk about the proper clothing. We could look at Matthew 5:28-29 or Romans 14:19-21 to talk about the proper influence. But, let’s think about the subject as it relates to 
Romans 8:29, which teaches that God “predestined [us] to be conformed to the image of His Son.”
Conformed to the image of Jesus!
How does one become “conformed to the image of Jesus”? In short, it is through the diligent study of God’s Word that one is “transformed into the same image [of the Lord]” (2 Cor. 3:18). When we immerse ourselves in HIS Word, we begin to take on HIS image.
Now, to modesty. If God’s desire is for His children to look like His Son, then shouldn’t we ask ourselves (when it comes to our attire), does this make me look like Jesus? Would Jesus wear this? When others look at me, can they see Jesus when I’m wearing this? If I wear something that detracts and is not conformed to the image of Jesus, that’s a big deal (1 Pet. 1:14-16)!