I did it the way that Way of the Master teaches how to do it. I met a woman at work, and she commented how boring the work line was, so I said, "How about we talk about deep stuff?" It was a pretty good lead-in, and I started, "Do you believe in life after death?"
From there we ensued. I only had time to bring her through one commandment (she liked to talk lol), and I explained to her that because we have broken God's law, that God cannot let us into heaven, the same way that a just judge cannot let a criminal go free. She looked at me with a shocked look and said, "That's not good!" She knew right then and there that she was in trouble with God, I could see it in her. I don't remember if I mentioned hell or not, but I do make it a point to talk about it. I then explained the gift of Christ to her, that He stepped in and took that punishment. She had to keep from crying, she was so touched by it.
We talked a bit more after break. She had to leave the line because she started crying. I haven't seen her since, but I saw the Holy Spirit do an incredible work right in front of me. She knew the law, she knew she fell short, that she was in trouble, and she broke down at hearing of God's grace.
It doesn't always happen that fast, but the Holy Spirit had obviously been working on her for a while, and I'm about 90% sure that if she didn't give her life to Christ that day, she soon would, but I haven't seen her since.
The last time I was out, I talked to three homeless people who I can see were well-tainted by drugs and alcohol. They were all sitting under a blanket. The spot smelled like urine, one of the guys couldn't talk straight (his beard was darkened around the lips from the drinking), and the woman with them, just no life in her eyes. I was with my brother in law and started out politely as we knew how. We started talking about sin and breaking the law, I tried the thing with the ten commandments. After explaining them a bit (ie. lust=adultery, hate=murder), the woman kept frequently saying, "Oh sh** I've done that." We talked about hell, we talked about heaven, we talked a bit about the issue of alcohol, and she kept saying, "I love my alcohol." She didn't want to give it up. Part of the difficulty is that homeless people in their condition have the attention span of a goldfish, and we were even told that by a street counselor, so after a half hour I estimate, it was time to move on.
I learned a few things worth mentioning. The biggest thing I learned is that when you mention sin, you will see people for who they really are, and they'll be confronted with their own conscience. The woman at work understood she was a sinner, saw the need to repent, and it was amazing. I was watching the Holy Spirit operating right in front of me. The three homeless people, well, when the cost was laid out, they didn't want it, because people do love their sin. At least the woman in the group. One of the guys was simply skeptical, and the other I'm not sure if he got it, he was too drunk (or affected by drink) and too incoherent.
A final witnessing tip: It's helps you in witnessing when you have a deep love for people, and it's essential. But there's something beyond that, that gives me more strength, and gives me boldness, and having a love, fear and respect of God to where I see the chief end of all things as bringing the most glory to Him as possible. Peopel are going to hell, and it's tragic, though what's also a great(er) tragedy is that God has been denied the glory He rightly deserves. All of a sudden, it's like you've become more concerned about the work of your Father and Master.