Living Waters. The evangelism methods taught here stress the importance of using the Ten Commandments to build conviction of sin, thus showing the sinner the practicality of Hell and his need of a Savior.
Ray Comfort wrote the book "Hell's Best Kept Secret" which expounds on this principle and why it is almost unheard of in personal evangelism today. Hell's Best Kept Secret is sold on Amazon for anywhere from $7 to $10 including shipping, and eBay from $5 to $7, including shipping. I highly recommend this book to ANY believer with a burden for the lost; I promise it is a worthy investment.
For all the penny pinchers out there who stubbornly refuse to buy one, as a penny pincher myself, I completely understand. You can listen to the audio for free on the Living Waters home page. It's not the complete book, but it's a general overview. Just go to the home page and on the right side you'll see a tab titled "Foundational Messages" with "Listen Now!" right below it. Hell's Best Kept Secret is the first message listed.
Using the Law to build conviction is very effective. I use this method every time I witness, simply because it gives positive results every time. It even works on believers! Consider the following scenario:
Bob: So, Fred, do you consider yourself to be a "good" person?
Fred: Good? Yeah, I'm a pretty good person!
Bob: Well, have you ever told a lie?
Fred: Uh... sure, haven't we all?
Bob: Sure! But what does that make you?
Fred: A liar.
Bob: Have you ever stolen anything? Even if it's really small?
Fred: Maybe once, when I was a kid. A pack of gum or something. You know... no big deal.
Bob: So what does that make you?
Fred: Um... a thief?
Bob: Exactly. Have you ever taken God's name in vain?
Fred: Well, yeah!
Bob: Have you ever lusted? Jesus said that lust is adultery of the heart.
Fred: I've done that.
Bob: Buddy, I've got bad news for you. By your own admission , you're a lying, thieving, blasphemous adulterer at heart."
Feel guilty yet? Whether you're saved or lost, the Law of God has a huge impact on your conscience. In this imaginary situation, Bob used only four of the Ten Commandments on Fred; just think of how using all ten could effect your lost friends and family! The point is to lead them to the realization of their sinfulness, which will in turn explain why they deserve to go to Hell and the reason they need a Savior.
If you're frustrated with running into a brick wall every time you witness to family or just curious about a new way to present the Old Story, give this book a try. It's short and sweet, but full of enlightening truth that you will be glad you found. I use this method every time I witness, and I see the Holy Spirit work time and time again. Even Jesus used the Ten Commandments to witness!