John 14:26 (New International Version)
26But the Counselor, the Holy Spirit, whom the Father will send in my name, will teach you all things and will remind you of everything I have said to you.
Research a popular TV show, movie, video game, book, singer, etc. NOW decide if you would expose your child to it. Don't let it stop there. Inform your child why you choose to watch the shoes you do and why you choose not to watch others.
Then ask your child "What if your friends ask you if you watch/listen to/play …?" Help them form an educated response. As they get older, "Because my parents won't let me" will become uncool; but a "I would rather …" or "I don't like …" response shows they are beginning to think for themselves, giving them confidence. It may not squelch all teasing, but your child will not feel completely out of the loop.
Prayer Suggestion: Ask God to give your child courage and wisdom in confrontation.