Watch Out for Repeats
Redundant and superfluous words can lose the focus and attention of your audience.
Be minded of how many times you rephrase what you convey in an attempt to get your message across. People will immediately pick up on repeats, get bored, and question whether you're trying to convince them or yourself.
Say what you mean and mean what you say.
It's good to set the tone and build upon your written prose or elocution. However, once you have, always leave room for one's spirit man to process the truth, thus, your audience will be quickened and edified by the meat of the message - God's Word.
The Holy Spirit will guide your audience into all truth.
Remember, the messenger is just that... "The Messenger". It's the message that holds its own power when delivered through the unction of the Holy Spirit. A biblical message of God in of itself penetrates and causes one to be renewed, encouraged and obtain wisdom by its very own power and ultimate authority.
Don't rewrite the Bible.
As Christian communicators we want to always reference scripture and Bible verse. This helps our audience to have a clear understanding of our topic of discussion, validating, we are not incorporating our own beliefs and adding context that's not scriptural. However, keep in mind, too many verses leads a person to think you may just be copying and pasting scripture. Communicate what the Lord has given you in your words. You have been gifted to do so.
Note: Triune, God the Father, God the Son, God the Holy Spirit, which are one, always work in conjunction to bring revelation, liberate and build up those who are eager and submissive to learn of God's ways.