Wise and Eloquent Preaching

Nearly every class I have taken, seminar attended or and piece of guidance that I have received about preaching has encouraged me to craft a sermon that is well written and smartly crafted. However when Paul reflects on his ministry, he writes:

For Christ did not send me to baptize, but to preach the gospel—not with wisdom and eloquence, lest the cross of Christ be emptied of its power. 1 Corinthians 1:17

How do you make sense of these, seemingly opposite sets of guidance?