"Hold them in the highest regard in love because of their work. Live in peace with each other." NIV translation
They say that teachers are some of the most unappreciated workers as they receive little pay and put in a bunch of time. Paul is telling us here to hold the Christian leaders (teachers) in the highest regard because of the importance of their work. He also tells us to live in peace but that does not mean we can't disagree on some things. As long as people believe in Jesus as the Son of God, then we should be able to work together for the kingdom. As John said, in his first letter, we are to test the spirits and there are only two sides.
"And we urge you, brothers, warn those who are idle, encourage the timid, help the weak, be patient with everyone." NIV translation
Paul continues with his list of things that should let others see that we are Christians. Warn the idle is talking about those that are saved but not actively serving the Lord. We are to tell them of the judgment of works that is to come and the rewards of serving God. Encourage the timid is talking about those that are shy or not bold in living the Christian life and we can tell them about the power in us through the Holy Spirit to do anything. Helping the weak is talking about those that do not have the abilities or financial means that we do and is how it was in the early church (see Acts 2:42). We are also to show patience and this one is very tough for some of us but we have to meet people where they are and help them to get to know Jesus or to grow in their walk with Him.
"Make sure that nobody pays back wrong for wrong, but always try to be kind to each other and to everyone else." NIV translation
We are to be like Christ and, just as He forgave us instead of condemning us for our sins, we are to forgive others. We are to be kind to brothers and sisters in Christ as well as those that do not know Jesus.
"Be joyful always; pray continually; give thanks in all circumstances, for this is God's will for you in Christ Jesus." NIV translation
Joy is not based on our physical surroundings but on our inner well being. When we are walking closely with God every day, the joy will just flow from us because of Him. To walk closely every day, we must constantly pray and worship God and give Him thanks no matter what is going on in our surroundings.