You are my witnesses, saith the Lord. (Isaiah 43:10) God will never call us to do something, without first showing us how it is to be done. Jesus showed us how to witness in the gospels and in the book of Acts he tells us that we shall be witnesses after that the Holy Ghost is come upon us. (Acts 1:8)
I understand the hesitation to witness of a person that doesn't have the Holy Ghost. But if we have received his spirit, then we have the power to witness.
Everybody is not called to be an Evangelist or Missionary, But we are all called to witness. We can witness to our relatives, our friends, our co-workers, our neighbors, and our acquaintances.
Some feel that they can witness by their lives without speaking about Jesus. However talking about everything else but God only reveals fear. Fear of what men may say or do unto you. There is no fear in love: but perfect love casteth out fear: Because fear hath torment. He that feareth is not made perfect in love. (I John 4:18)
My brothers fear not what people may say or do unto you. Countless saints have been tortured to death, because of their beliefs. They did not let a little thing like suffering a horrible death, stop them from testifying. At the risk of making you more afraid, let me tell you that the fearful shall be the first that will have their part in the lake of fire which burned with fire and brimstone. (Revelation 21:8)
Out of the abundance of the heart the mouth speaks. If Jesus is in your heart, then he will come out of your mouth. Be not ashamed of Jesus or else he will be ashamed of you before his father. (Luke 9:26)
If you really love your family or friends, then you would not want them to be destroyed forever. To become an effective witness you must be convinced that unless people come through Jesus Christ, they are lost forever. You must totally lose any hope that perhaps there is some other way. Your grandma may be the sweetest lady there is, but unless she comes through Christ she is totally lost.
Go ahead and step out in boldness. Jesus is with you, and he will guide you on what you should say. You will surely see a harvest of souls.