R Scott Clark offers some excellent advice for student preachers. He offers the following eight suggestions:
1. Determine from the text the one, central, unifying theme of your passage.
2. Preach only one sermon at a time.
3. Remember your congregation.
4. Keep your head up (and leave the manuscript at home).
7. Learn the difference between law and gospel and how those two “words” relate in your passage.
8. Be careful in application.
Read the entire post with further explanations here.