Jumping on every opportunity to share the gospel, getting in everyone's face with the truth, plastering the town with tracts... Sometimes I think that evangelists want to test God's ability to save by driving away those they are witnessing to.
While the gospel must be preached, it must also be lived.
You can see the Spirit in the person who watches for signs that their "target" for conversion has had enough. You are not loving your neighbour by wearing them down until they accept Christ just to get a rest from you.
God will ensure that everyone who will be saved will hear the Word. You concentrate on being a graceful and loving ambassador who lives the gospel as well as speaking it. In this you will see the Spirit.