One of the things that I hear about a lot, is when people worry about how others view them, and what they think of them. And same the advice I hear all the time is, "It doesn't matter what they think of you." That is true, to some extent. We still have to let our light shine. And, if we dress of the world, then we're showing others that we are of this world. There is a difference between someone thinking that you're of this world because they just don't like you, and thinking you're of this world because you act like it, or dress like it. I said this a little while back, that, if you went to the beach, and saw someone wearing a bikini, would your first thought of them be, "Oh, they must be a Christian." Obviously not. But, if you go to a beach and see someone in board shorts that go to their knees and a rash guard shirt that covers them, then are you going to have a little more respect for them, and their purity? If you dress like the world, people are going to see that you are of the world, because you're presenting yourself that way. Matthew 5:16, "In the same way, let your light so shine before others, so that they may see your good works and give glory to your Father who is in heaven." This verse is telling us that, if we act like we're God's children, then people will see that.
Before you do anything such as, watch a movie, buy some clothes, read a book, or even post a status on Facebook, think of someone you admire for being Godly, and think, "Would they be okay with this?" "Would they watch this movie?" or, "Would they wear this shirt?" or "Would they read this book?" etc. Because, if you do that, then you are motivating yourself to do what's right in the sight of God. I'm not saying that we have to be perfect, but we at least have to try to be. Please keep this in mind next time you get dressed. :)