This kind of teacher is consistently true to an historic Christian and balanced biblical doctrine. Typically, a Sound Teacher is marked by an objective and honest approach to handling both the basics and the advanced aspects of Scripture. Sound teachers are generally those men whose ministry has stood the test of time.
These teachers possess an extremely high view of God’s Word and are very conscious of the importance of sound doctrine, regularly encouraging discernment and pointing out error. It is this sensitivity that drives them to fiercely protect the saints from falsehood and equip them for the devil’s attacks on God’s Truth. This sensitivity is also what causes them to continually pursue clarity on every Biblical topic that the Bible addresses. This is not to say that they are never wrong or that other Sound Teachers will not differ on some points of interpretation or application. The Sound Teacher should be the first to admit this.
Sound Teachers are to be looked to for mature spiritual understanding and the wise application of Biblical truth. You will want to read and listen to them as you have more in-depth spiritual and Biblical questions, however be sure their teaching is only a supplement your own study, and that you remain submitted to the sound (or if necessary, safe) teaching and authority of your own pastors.
It is important to realize that every teacher either believes or claims to be a sound teacher according to their own criteria. You be the judge. Be a Berean.
Sound Teachers ought to be your pastors. That said, there are not as many of these men as there are local churches, so you may find yourself in a place to submit to the leadership and teaching of a Safe Teacher. This is not necessarily a bad thing as long as he is surrounded by other qualified elders/pastors who, together, are humbly seeking the Spirit's leadership and the truth of Scripture. In addition, as a discerning Christian, you should actively be praying for, serving, and humbly holding believers accountable to Scripture.
Acts 2:37-41 - Now when they heard this they were cut to the heart, and said to Peter and the rest of the apostles, “Brothers, what shall we do?” And Peter said to them,“Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself.” And with many other words he bore witness and continued to exhort them, saying, “Save yourselves from this crooked generation.” So those who received his word were baptized, and there were added that day about three thousand souls.
1 Corinthians 2:1-5 - And I, when I came to you, brothers, did not come proclaiming to you the testimony of God with lofty speech or wisdom. For I decided to know nothing among you except Jesus Christ and him crucified. And I was with you in weakness and in fear and much trembling, and my speech and my message were not in plausible words of wisdom, but in demonstration of the Spirit and of power, so that your faith might not rest in the wisdom of men but in the power of God.