Don’t Preach. Teach!
“I have learned silence from the talkative, toleration from the intolerant, and kindness from the unkind; yet, strange, I am ungrateful to those teachers.” – Khalil Gibran
You cannot easily change another human being, especially if you seek to do it by preaching.
You can attempt to influence others in ways you think would benefit them. You can try to act in a manner and make decisions that would serve as a positive role model.
But you must do this, knowing the difference between teaching and preaching. While the former means sharing your wisdom out of love and care, the latter seeks to convert, convince or coerce.
So, do you want to change another person? Don’t preach; teach, especially by example!