From FB of Shakh Yasir Qadhi:
Once, the Caliph `Umar saw a group of people around a campfire in the middle of the desert. Instead of calling out to them with the phrase, 'O people of the fire!', he chose, 'O people around a light,' to make sure that a potentially negative phrase didn't affect them.
At another time, the grandsons of the Prophet (salla Allah alayhi wa sallam) saw an old man performing wudhu, but making many mistakes. Instead of berating him, they went up to him and said, 'The two of us are arguing which one has the better wudhu, and we'd like you to be the judge between us.' When he saw how perfect their wudhu was, he said, 'It is my wudhu that needs to be corrected, not yours.'
A famous preacher of the last generation - during a time when there was a raging debate regarding the theological verdict of the one who abandons the prayer, is he a Muslim or not - was asked, "What is your opinion about the one who abandons the salat?" The person that asked him was not a scholar, but rather someone who listened to debates and liked to revel in his self-taught knowledge. The Shaykh smiled and said, "My opinion is that we should hold on to the hand of the one who abandons the salat and encourage him to come to the masjid with us!"
A lot of times, its not the message itself, but how you present it, that moves hearts and changes minds. And not every single controversy needs to be laid out in front of every single person: speaking to your audience correctly is half of knowledge.
May Allah grant us the wisdom to preach in the wisest and best of manners!