I think we should speak with people who express interest or seem receptive to learning about Catholicism. One has to use discernment in choosing those to whom we speak. Remember, Our Lord didn’t go to certain places because He knew they had no faith and were not of good will. Also, be careful to maintain charity, not to slide into judgements and threats of condemnation unless that’s really indicated. Defend the Faith in situations where that’s called for, but don’t pick a fight. Ironically, it’s often easier to speak with others who don’t know you than to try and convert relatives or close friends.
Another issue is to ask yourself if you are qualified. Even if you can recite the entire Baltimore catechism by heart, that isn’t going to convince anyone unless you can explain the reasons for believing this and not that. If dealing with Protestants, you’d better be very familiar with the Bible and the differences between Catholic and Protestant interpretations of key portions. A working knowledge of Church history comes in handy as well.
Most of the time, the best way to convert others is to set the best example.