It is interesting to listen to the notes that Paul sounds in these verses. They tell us a great deal not only about objective priorities in local church ministry but also the kind of emphasis that these priorities demand from us in our thinking, praying, preaching, pastoring, admonishing and relating to our people.
One thing that stands out is Paul's insistence on what we could call the "clear and present danger" of false teachers. Church leaders should expect trouble in this form. So Paul exhorts them to "pay attention" to themselves and to the flock, and to "be alert." Or, in other words, don't be naive about error, don't be negligent or complacent.
Confrontation with error is going to happen to you at some point in church leadership. And it will involve confronting people not just ideas. When it happens do what Paul does. Don't count your life as precious and valuable (20:24). Count the flock of God as valuable because it has been obtained by God with his own blood (20:28).
False teachers are fierce wolves who will not spare the flock (20:29). Don't waste your church by failing to spot the pelt underneath the fleece. Don't waste your church by being soft on wolves.
Chris Green has some helpful words on this in his helpful book The Word of His Grace: A guide to teaching and preaching from Acts:
Christians today take many things seriously: there are wonderful teaching resources, and there's great music available. We are encouraged to do evangelism well, and there are practical courses available to help us, and there are organizations that will use our money and time to keep the practical arm of the church's programme supported.
We take ecumenism seriously, and the arts seriously, and the family seriously, and drugs seriously--and we hardly think to take the danger of heresy seriously. The danger of wolves in shepherd's clothing. And it is a real danger...which means that all the other things we do take seriously are ruined. I think if we knew more about farming this image would scare us silly.
Now, of course, if we saw that kind of destruction coming we'd be careful and avoid it, but these savage animals are very nice people.