"When they saw the courage of Peter and John and realized that they were unschooled, ordinary men, they were astonished and they took note that these men had been with Jesus." (Acts 4:13)
I think this is such an encouraging verse in the Bible--to see that God chooses and uses "unschooled and ordinary" people. It is easy to convince ourselves that we aren't "theological" enough to share the gospel or participate in the ministry He is calling us to do. God calls us to make disciples of all the nations and that is not a command for a few. That command is to all of us in whatever type of job or vocation He has placed us. Peter and John's confidence did not depend on theological degrees or upon being perfect--they simply had been with the Lord.
To make disciples means we must first share the gospel, but ALSO to follow up with them until they are ready to share the gospel and follow up with another person. In order to do this, we just need to be one step ahead of the other. For example, I am not a golfer, but if I saw a person trying to hit the ball with the handle of the club and the putter at the top, I at least know enough to tell him or her that the club is upside down. In a similar way, we need to take whatever we know and teach others. Think about how you could use what you know and where God has placed you in order to invest in another person.