The Apostle Paul was a great witness for the Lord, and almost every single time that he was brought before kings and judges, he invariably started his witness with his own personal testimony: "This is what happened to me!" (See Acts 26.)
People are interested in people! Life stories are more effective in witnessing than getting into theological arguments and preaching sermons. When you start telling people your life story, "This is what happened to me and this is my testimony!", instantly you have their attention, they're fascinated. When you tell them your own personal experience, if you say it with sincerity in the power of the Spirit, they will believe that you're telling the truth!--Your testimony is one thing they cannot deny! And the moment they confess that it's happened to you, then they can confess that it's possible for it to happen to them! Win them to yourself and your own happiness first, then they will want what makes you that way!
You're the proof of the pudding! You are the product of the Gospel and the Love of Jesus!--So tell others of how His miracle-working power has worked in your own life, as a genuine living sample and proof of what He can do!