The human tongue can be a powerful instrument for evil, as explained in James 3:1-12. But it can also be used for good. We can use it to encourage people (Hebrews 10:24,25; 2 Corinthians 1:3-7; 1 Thessalonians 5:11). We may also need to correct people (Galatians 6:1; 2 Timothy 2:24-26; Matthew 18:15-20). There are also instruction and evangelism, but to look at those is too much for one post. Now all these need to be done in love (Matthew 22:37-40; Romans 13:8-10; Galatians 5:13,14).
To encourage people we need to have sympathy (Romans 12:15,16; 1 Corinthians 12:24,25; 1 Peter 3:8). This can be hard, because if you really sympathize with someone, you hurt with them. We need to start by listening. If we do not listen to them, they will probably not hear what we have to say. But it is so much easier to come up with a quick cliché and walk away. A Bible verse can be used as a cliché for this purpose. Now I am not against using Bible verses to encourage people. But we need to show we care before we bring out the Bible verses. I remember one time I was in the hospital and I was visited by a pastor, a former pastor, and a pastor in training. They all read me some Scripture, but they spent time first talking and listening. After that, the Bible passages were a good thing.
Correction can be even more difficult. In this respect I am convinced it is important to follow Matthew 18:15-20 and to start with a meeting between the accused and the accuser. Also, the part about winning your brother implies there needs to be some give and take; an effort needs to be made to convince the person that they are wrong. There should be some effort made to give them a chance to present their side of the story (Proverbs 18:17; 25:8-10). But even if what they have done is indefensible, they may need clarification; they may need to know if their repentance and offer to change or make amends satisfies the accuser. There is no way they can do this through a third party. In the Old Testament the accusers of a person were to be the first ones to pick up the stones to stone them (Deuteronomy 17:7). Also, if the accusation was false there was to be an investigation to see if it was deliberate, and if so, the accuser got the penalty sought for the accused (Deuteronomy 19:15-21). The point is that anyone making an accusation against anyone should confront them openly and directly. Now it might be said this is hard, but making an accusation is meant to be hard. There is a place for passing over minor offenses (1 Peter 4:8). But if we need to correct anyone, we need to do it right.
There are many positive ways to use the tongue, but they must be used carefully to be done right.