People often shy from witnessing because they are afraid others will ask questions they cannot answer. In John 4:39-42 we find an answer to that. People witness to people on their own level, in their personal understanding. The woman at the well is no different, and you should have no other personal expectation for yourself.
In John 4:39 the woman at the well talked to a few folks in Sychar and simply told them to come see the man which, “Come, see a man, which told me all things that ever I did: is not this the Christ?”
On the way there, someone would have asked more questions such as, what else did He tell you or is there anything else you talked about. She probably told them of the living water unto eternal life, and worshiping in spirit and in truth. Regardless, their statement in verse 42 says they did not believe until they came to the place where Jesus was for themselves, willingly listened to His truth, purposefully sought His teaching.
I have only personally witnessed a couple of dozen individuals come to the knowledge of Christ through my witness. It is not that I do not tell others about Jesus, I do that all the time. However, many either claim Him already or are not properly prepared for my witness. In this case, the town was ripe for the harvest (John 4:35).
Tell people you know Jesus and what He has personally done in your life. Let them know of His great love and the changes He has made in you. Tell them of the Savior of the world who came to forgive not to judge. The best witness is personal, specific and simple. That is what the woman at the well did. Her initial witness to some town-folk ended up that many came and believed upon the Savior. You don’t have to be a theologian, you simply have to believe and show the zeal of your faith. Take them to the well, let Jesus do the heavy work.