Example in Conduct

Let no one look down on [you because of] your youth, but be an example and set a pattern for the believers in speech, in conduct, in love, in faith, and in [moral] purity.

When Queen Victoria was a child, she didn’t know she was in line for the throne of England. Her instructors, trying to prepare her for the future, were frustrated because they couldn’t motivate her. She just didn’t take her studies seriously. Finally, her teachers decided to tell her that one day she would become the queen of England. Upon hearing this, Victoria quietly said, “Then I will be good.” The realization that she had inherited this high calling gave her a sense of responsibility that profoundly affected her conduct from then on.

Your conduct is the way you behave, the way you carry yourself around. Your conduct is what you project out for the world to see. When you and I proclaim to be born again, then automatically there is a way that people expect us to behave because of who we proclaim to follow.
Paul is telling Timothy to be an example to the believers in the way he lives his life. As one man once said, “Your life is the loudest sermon you will ever preach.” How can you show others the way if you yourself don’t know the way? We are to put off the old man who is corrupt according to the desires of the flesh.

Ephesians 4:22 (AMP)
22 that, regarding your previous way of life, you put off your old self [completely discard your former nature], which is being corrupted through deceitful desires,

The way we live our life, the way we interact with others and how we treat them, what we do when no one is watching should all be above board.
The world is looking for role models and Paul is telling Timothy (you and I included) to be that role model that others would desire to be like because of how we live our life. The change can only happen when we allow the Holy Spirit to reign in our lives. It is when we do so that the fruit of the Spirit becomes evident in us through the way we interact with others.

Galatians 5:22-23 (AMP)
22 But the fruit of the Spirit [the result of His presence within us] is love [unselfish concern for others], joy, [inner] peace, patience [not the ability to wait, but how we act while waiting], kindness, goodness, faithfulness, 23 gentleness, self-control. Against such things there is no law.

Just like with the queen in our story, you and I are Gods ambassadors here on earth and our conduct ought to reflect that!