Peter writes that we should minister to one another according to the ability God has given us (1 Peter 4:11). We have varying abilities, even in the same ministry. For instance there are speakers/teachers whose ability draws crowds of thousands to hear him/her. There are speakers/teachers who minister to 20 or 30 people. And there are speakers /teachers whose ministry is discipleship, ministering to one or two people at a time.
Contrary to American perception, God decides both our ministry and the size of the span of our influence. We need to study to be the best, but remain content on the number of people we reach.