In one of our outreaches, a missionary asked why people respond to altar call en masse whenever I preach. He said he observed that I achieve that result effortlessly but another preacher he knows who does same doesn't get the same result.
I told him the only secret I have in that regard is prayer. I told him that long before I step on the pulpit to preach on mission fields, intercession for souls would have gone ahead of me months before I preach. This includes fasting as well with my prayer team. I know no other way to winning souls than through soul-hot intercession.
Preaching the gospel without adequate praying is like pouring water into a basket. It will never be filled.
That reminds me of Father Nash, the personal intercessor of Charles Finney. Those days when Charles Finney held crusades in towns, villages and cities, Father Nash would go ahead of him to those places he'll be preaching. He will rent a room or find a place to pray. Sometimes, he'll be there three weeks ahead doing nothing but praying and groaning for the salvation of souls.
In church history, Charles Finney was one of those evangelists whose meetings were characterized by sober repentance without much words. I once read that in less than fifteen minutes of preaching, souls would get on the floor asking the Lord for mercy. Why? Because a man prayed them into that encounter.
Those that do not understand the secret of Charles Finney would think the results he got were products of eloquence and oratory skill.
The gospel in the mouth of an orator is just another fine speech but in the mouth of a praying stammerer, it is the power of God unto salvation as it should be.
When dealing with unsaved people, well crafted words and eloquent speeches doesn't get the job done. No man has the power to make another man yield to the call of salvation without engaging the power of God. The heart of the fallen man is stony and it can only be broken through prayers.
As you set out to preach the gospel and engage men, your knee work must be more than your mouth proclamation. You cannot force conversion neither can you stir conviction with eloquence. If you have someone you've been trying to win unto the Lord, start the work on your knees and continue on your knees.