Long ago, the wind and the sun decided to have a challenge to see who was more powerful. So they looked to the earth and saw a man wrapped in a cloak walking along a path and felt that this man would make a good example as to who was the more powerful of the two. They decided to see who could get the man to remove his cloak first.
The wind decided to go first and tried to blow the man's cloak off of him. When it wouldn't come off, he blew harder and harder with all his might and could not get the cloak off the man. In fact, the man only drew the cloak tighter and tighter to his body. When the wind exhausted all of his might, there the man sat with his cloak wrapped tightly around him still.
So the sun took it's turn and just shined on the man with no effort...just a nice warm glow. After time, the man began to loosen his grip on the cloak. Then after a while longer, he began to sweat. And finally after some waiting and some patience from the sun, the man finally removed his cloak thus declaring the sun the winner.
The moral here is that when dealing with people (in dawah or otherwise), approaching them with harshness will only cause them to draw further away from you and make them more tight-lipped. The key is to have sabr and give the charity that all can give whether rich or poor...a smile. Then people will be more open with you and share what is in their hearts, thus causing you to be able to know the real; the only thing worth truly knowing in any of us.
May Allah guide us all.