Styles...fashion...fads...seasonal apparel..."in" clothing...out-of-date...
What do you think of when it comes to clothes?  Some could care less; for others it gives them popularity, attention, and the significance they desire from other people.  Let's see what you think of when I throw another word in here: modesty.  Does that change the image of clothing in your mind?
In the homeschooling movement today there are all different aspects of how families ignore or embrace the issue of modesty.  Some families believe that what's in the heart is most important and so don't give any guidelines or restraints for their family.  In an article , entitled The Spirit of Modesty, author Jeff Barth writes that these type of people "in a sense turn the grace of God that is given to us to produce righteousness in our lives into a `license' to live pretty well however they feel or choose.  A major problem with this way of thinking is that this license often surfaces in the form of excess rebellion or worldliness in their children and grandchildren."  Barth also points out that some families have taken the opposite approach to modesty by following strict legalistic codes.  The problem with this approach is that you (or your children) can be strictly modest on the outside, but not have a modest heart.  Both extremes are out of balance with what the Bible teaches us.  Neither will bring about true modesty.

Going deeper...
I think the word "modesty"can be somewhat distorted in our minds.  The world considers modesty as "prudishness," "old-fashioned," or too "strait-laced."  Maybe even your church has given you the feeling that modesty is "out of style."  It really broadened my mind when I decided to look up the word "modest" in the American College Dictionary.  What I found went beyond the limit of a person's clothing or "style":
"Modest.  1.  having or showing a moderate or humble estimate of one's merits, importance, etc., free from vanity, egotism, boastfulness, or great pretensions.  2.  free from ostentation or showy extravagance.  3.  moderate.  4.  having or showing regard for the decencies of behavior, speech, dress, etc.; decent."

In the Beginning...
Did you know that God was the one who instigated modesty?  Until sin entered the world and marred the perfect creation God had made, there was no need for clothes made by man. (You can read more about it in Genesis 1-3.)  Some Bible scholars believe that Adam and Eve were "clothed" by God's holy light (The Discovery of Genesis by C. H. Kang and Ethel R. Nelson, pg. 42).  When Adam and Eve marred their perfect relationship with God by sinning, they realized their need for some kind of covering as God's glory left them.  Although they tried to make clothing out of fig leaves, it was not sufficient enough, nor did it hide their sinful deeds before the Lord.  After God confronted them about their sins, He provided better clothing for them, made of animal skins- which also indicates God showing them that there must be shedding of blood (a sacrifice) for forgiveness of sins (atonement).

The heart attitude...
When we accept Christ (the Perfect Sacrifice) into our lives, we confess and acknowledge our sins and pride.  A modest heart, like the dictionary showed us, will not have sinful pride over one's self, talents, or body.  Therefore, if we are truly saved, our hearts should display modesty in all areas and aspects of our lives such as: our speech, clothing, looks, actions, manners and behavior.  When we give our lives to Christ, we are really surrendering all to become a new creation in Christ, leaving behind the old nature with its sinful pleasures and ways.  "Therefore, if anyone is in Christ, he is a new creation; the old has gone, the new has come!"  2 Corinthians 5:17
Now as a new creation redeemed in Christ, we are to represent our Savior to the world!  "We are therefore Christ's ambassadors, as though God was making His appeal through us." 2 Corinthians 5:20
As Christ's ambassadors to a lost world our lives should then be a reflection of our pure and Holy God through our hearts, our motives, actions...and yes, even our choice of clothes!

"Displaying" modesty...
As we have seen, modesty was instigated by God and if we are His people we should display modesty in our lives.  Yes, it starts with our heart, but if we are truly seeking to please God, we should also be willing to let the modesty in our heart shine forth to our outward appearance so that the world can see our genuineness, i.e., we live what we believe! 
"Man looks at the outward appearance, but the Lord looks at the heart." 1 Samuel 16:7b
Can both God and men see that you display modesty in your life?  Dressing modestly shows our desire to be pure.  As Christians we should have all made a commitment to purity: for those who are married it is a commitment to their spouse; for singles it is to keep their purity/virginity for their future spouse if God should lead them to marry.  Therefore there should be no room for immodest apparel in the life of a Christian that would cause others to sin.
Christian men are having enough struggles in this area as many Christian women in the Church today have accepted blindly (or not) the current styles that are often very immodest.  Girls, let's not cause our brothers in Christ to stumble by taking their eyes off of God. If we Christian women and girls dress modestly we give a statement to boys and men (whether they are Christians or not) that says we desire purity for them as well.  Our purpose by dressing modestly, simply, and attractively is to let Christ's beauty radiate through us and not to cloud that with seductive or "look-at-me" clothing.  Our goal as Christians, both as men and women, boys and girls, should be to point others to Christ without any distraction on our part.
"I want men everywhere to lift up holy hands in prayer, without anger or disputingI also want women to dress modestly, with decency and propriety, not with braided hair or gold or pearls or expensive clothes, but with good deeds, appropriate for women who profess to worship God."  1 Timothy 2:8-10

Cultivate modesty...
Because the world is bombarding our families with so much immodesty we need to take action by cultivating it everyday at home.  Modesty should be encouraged and not discouraged by "things" we have in our homes such as:
-books we read
-TV or movies we watch
-magazines we buy
-toys children play with  (a note here: what we allow children to imagine in play will later show in how their character is formed.  Satan can deceive people in thinking "it's just a toy.")
-art/ pictures we exhibit in our homes (Like the saying goes, "a picture is worth a thousand words," so your pictures should be Christ-honoring and help people to think on things that are lovely, pure and noble (Phil. 4:8).  Don't be fooled into accepting pictures that are so-called "art."
Modesty needs to be encouraged at a young age because, as we have seen, it is a whole-heart issue rather than something that is governed by a lot of rules.  Young or old we need to demonstrate it in our own lives.

Actions show the heart...
As you prayerfully are open to God to help you dig further into the heart of modesty, let me suggest that you take a look at your actions - and the motives behind them.  Do they show modesty?  I have observed both boys and girls, and men and women who act immodestly by their brashness or look-at-me ways.  Too many ads, magazines and catalogs display people with an "in your face" type of look.  What this lost world needs are more Christians who show by their actions, their speech, and even how they walk, that their hearts are pure and God-centered (not me-centered).  A practical way to apply this is to also develop good manners. 
"Even a child is known by his actions, by whether his conduct is pure and right."  (Proverbs 20:11)

Clothes...
I am so grateful to God for giving me a wise mother.  Mom guided us kids at an early age to learn modesty in dress and actions - as well as our heart.  She also has great taste, I think, in helping pick out clothes; finding nice, attractive clothing that is neither out of style nor dowdy, yet is still modest.  If you are a parent, pray for wisdom and discernment for how you should guide your children in becoming modest.  Here's some advice Mom shared with me about this area:
-When children are little, don't buy clothes that would be immodest on a teen.
-Have standards.
-Keep it simple and be consistent in your own life.
-It's more fun to be creative than to blindly follow every current fad.
Dressing modestly is one of the ways that we're walking the narrow road, that Jesus speaks of in the Bible (Matt. 7:13-14).  It is very hard to find modest clothing nowadays, but don't use that as an excuse to dress immodestly.  Present your need to God for help in the area of clothing; there is not one little thing God can't do (Phil.4:6).  Mom taught me to use creativity in finding ways to dress modestly.  Together we have spent time combing through stores, even looking at second-hand stores, and garage sales, as well as sewing our own clothes.  Even though it takes "some doing" you would be surprised at the stories we can tell of how God has provided for us in this area.
There are no straight and fast rules in this area of clothes.  I am finding out that I continually need to pray for wisdom from God as I'm making a lot of my own decisions as a young woman in choosing what to wear.  (Of course, I often check with my mom or dad if I have doubts about something, but I often need to watch my inner heart motives, e.g., "Do I want to just draw attention to myself by wearing this?")  We need to be continually reminded to not "conform any longer to the pattern of this world" (Rom. 12:1-2) by accepting the latest styles.  A way to do this practically is to look through your closet, your dresser, or at something you want to buy in the store and ask questions about each piece of clothing:  "Is it modest?"  "Where does it draw peoples' eyes to?  -That is, upward to my face and eyes ("the windows of my soul") or somewhere else?"  Looking at the lines of a garment will give clues.  Remember that you can be totally covered, but still look immodest if the garment is too tight.  Even though a dress is long, if it has a long slit, it can be suggestive, and therefore is not modest.  Also, I must say that I have seen too many people -both guys and girls- who are not ashamed to show off their underclothes.  You can be sure that any clothing that shows off or doesn't cover undergarments is definitely immodest.  A word of encouragement here for children and teens is to listen to how your parents are guiding you.  Girls, your mom and dad probably will know a lot more than you do as to what kinds of clothes are immodest and would cause the wrong kind of attention.  Boys, you need to be modest too!  There are too many guys out there who are wearing jeans that are almost falling off.  Not only does it look sloppy, but it's a very immodest way of dressing!  If your parents have misgivings about some kind of clothing, honor them by not wearing it.  God will bless the heart that desires true modesty!
"Flee the evil desires of youth, and pursue righteousness, faith, love and peace, along with those who call on the Lord out of a pure heart."  2 Timothy 2:22