Most preachers and teachers want to do their work in the best, most effective way possible. There are a lot of helps available for them - better techniques, finding a better process in preparation and delivery. All that is good, but it isn't of prime importance. God-honoring, effective preaching and teaching comes from a certain type of life, not just from a process or techniques.
When I speak of it coming from a life, I don't mean only a moral and ethical life (as described in 1 Timothy 3 and Titus 1) - though that comes first. The kind of life that produces effective preaching and teaching has specific characteristics related to the work of a teacher. Here are seven character qualities I think that are important.
God-honoring teachers will be honest with the text. They will take it for what it says, not for what they wish it said. For example, when we come to 1 John 5:7-8 in the King James (or New King James translations), we must be honest with the difficulty of the text. Though the Trinity is definitely a Biblical truth, we must be honest and say that 1 John 5:7-8 doesn't address the Trinity in the way many hoped. I might wish that it gave me an airtight statement of the Trinity, but the textual evidence says otherwise. If we are not honest as expositors we will be prejudiced, manipulative, and careless.
If we don't have a sense of security of who we are in Jesus and in the power of God's Word, we will never please God with our work as a preacher or teacher. Paul recognized that living to please men and living to please God don’t go together (Galatians 1:10).
To fulfill your ministry as a preacher and teacher will take many years of hard work. You can't be lazy or always look for the easy way out. You must be able to do the hard work of study and preparation time. It's not just a matter of time (though that is part of it), it is also a matter of focus and concentration.
The effective preacher and teacher will have a sense of boldness; not arrogance, but a genuine confidence in God and His word. The boldness does not come from any confidence in self, but from a justified confidence in God. The timid or hesitant preacher simply will never fulfill their ministry as they could.
If you don’t care much about what you are teaching, why should anyone else? God forbid that we should conjure up a fake passion or enthusiasm. God's word is filled with greatness on every page. If you can't see it and have a genuine sense of its goodness and significance, don't blame your hearers for their boredom.
The effective preacher and teacher will keep pressing on to learn. They will not have the sense that they have “arrived”. They won't have a sense of self-confidence, self-assurance, or self-satisfaction. Like Paul in Philippians 3:13-14 they will keep pressing on, pursuing the high call of God in Jesus Christ
In Hebrews chapter four, verse 15 describes the priestly ministry of Jesus towards His people, telling us that He can sympathize with our weaknesses. If Jesus has this sympathetic heart towards man, so should his messengers have this same heart when they preach and teach. They should think through how things will sound in the ears of those who hear them, and seek to persuade them. More than eight times the Book of Acts speaks of the persuading work of Paul, and you can't persuade unless you have some sense of how your hearer thinks and feels. The unsympathetic preacher will be perceived as being rude, hard-hearted, and harsh.
If someone has these seven characteristics, there is much they can learn and grow in as a teacher or preacher. Without them, all the best techniques or technologies will not be effective to fulfill one's ministry.