"What, after all, is Apollos? And what is Paul? Only servants, through whom you came to believe - as the Lord assigned to each his task. I planted the seed, Apollos watered it, but God made it grow. So neither he who plants nor he who waters is anything, but only God, who makes things grow." NIV translation
It seems that many times we forget the most important thing and, here, Paul reminds the believers that it is not about who led them to the Lord but it is about God who called them. Without God's call on our lives, we would not come to Him no matter what anyone else did.
"The man who plants and the man who waters have one purpose, and each will be rewarded according to his own labor." NIV translation
Both the preacher and the teacher have the same purpose and that is to help people in their walk with the Lord. It is not a contest as each will be rewarded for how they used their gifts for this purpose (see Revelation 20).
"For we are God's fellow workers; you are God's field, God's building." NIV translation
Its all about building up God's people which is "the church". We see, here, that Paul never looked at the church as a building so we must ask ourselves why so many think of it that way today. When you start to think of the church as a building, then, you get the struggles between different buildings that are each trying to be "the church". That division is the same thing that was going on here in Corinth and it is not of God but of the enemy.
"By the grace God has given me, I laid a foundation as an expert builder, and someone else is building on it. But each one should be careful how he builds." NIV translation
Paul explains that he led people to Jesus (evangelist) which is the foundation of our faith. Then, others (pastors) were raised up to help them in their day to day walk in the faith. Paul was responsible for the task that God gave him and those that were called to be pastors were responsible for that task. The same goes for us today in that we are only responsible for what God tells us to do and we are to do it well because it is for Him.