Family and Friends
This is probably one of the more difficult situations in regards to witnessing. Family and friends who have seen your manner of life may wonder what in the world has gotten into you. They may think what your going through is just a fad and that in due time it will pass and you will be like your old self.
One of the first things we want to do is make sure our walk matches out talk. Believe me, they will look at you and look for any area of your life that doesn't line up with the profession you make. The reason, they want to say to themselves, "see look what he did", if he did that and claims to be a christian them I'm a christian to. In other words, they will look for areas in your life where you fall short so as to build themselves up and ease their conscience.
We realize that as Christians we will fail at times. When we do it is important to confess and be humble showing them that we are a work in progress. I think when people see someone willing to admit their sins and come clean it speaks volumes. This may even show them that something is very real about you in your willingness to be transparent.
Another thing we must do is be rich in good works toward them and others. When they see the sacrifical love that we have for our fellow man that speaks to the realness of our profession in Christ. These things may open the door to be able to speak the truth into their life. Another and probably the most important thing to keep in mind is prayer. We must be diligent in praying for them and also that God would open the door to speak.
These are things that can have an impact on our being able to witness to our loved ones and friends. However, nothing replaces the speaking of God's word to shed light on their soul. The best way to do this is to share your testimony with them. One of the things that they cannott argue with is the fact that your life has radically been changed since coming to Christ. We have the "word of our testimony."
It is wise to say that you came to realize you were a sinner and then explain what sin is. This way as your sharing your teaching as well. You may want to ask them if they have sinned against God, etc.. Certainly they would not say they haven't. Another wise thing to keep away from is speaking about their denomination or their beliefs. That will get you nowhere. However, you can tell them that you also came to realize that church attendance, baptism, sacrament keeping, can in no way earn salvation or make one right with God.
When telling about what Christ has done in your life be sure to show them, that this is an affect of being "born again." That you would have no strength within yourself to turn from your sin had it not been for God's grace in Jesus Christ. And that the desires for the things of God and knowing him come from the Holy Spirit that God said He would give when one repents of their sins and comes to Christ for salvation. Ask them what they are relying on for their salvation, etc..
In closing, be gentle with your loved ones and understand they are like anyone else who hasn't been awakened by the Holy Spirit. They are blind and cannott see, their view of God is darkened because of sin. Also, they need to understand that Christ didn't come to necessarily give us a better life, but to save us from our sins and grant us eternal life. We need Christ to avoid the wrath of God. This is the true need for Christ and in love we must present it in truth.
Other things you can do to plant seed, is give them a book and tell them this really helped you understand God more. That may spark their interest in reading it. Make sure it has the gospel clearly defined and is God glorifying not man centered. Other things you can do is, invite them to outreaches where a minister of the gospel will be speaking, or Bible studies, etc.. Don't be overbearing, but be led of the Holy Spirit.
May the Lord bless you in your efforts to reach your family and friends for Christ.