“Upon that law doth he meditate day and night” (Psalm 1:2).
“Abide in me and let my word abide in you.” — John 15:1-10 (spoken or implied throughout these verses)
“Eat this book.” (Ezekiel 3:1)
Get God’s Word inside you.
The best thing you can do to prepare to preach or teach a text is to live in it for many days prior to the moment. This means reading it again and again until you know what it’s saying. After that, read it again until you see even more.
Then, you think about it, reflect on it, meditate on it. You go to bed thinking about it, you mull it over while driving, and you talk to the Lord about it while praying.
Read it slowly. Read it aloud. Read from various translations and paraphrases.