"And the prayer of faith will save the sick person, and the Lord will raise him up. If he has committed any sins, he will be forgiven. Therefore, confess your sins to one another and pray for one another, that you may be healed. The fervent prayer of a righteous person is very powerful." James 5:15-16
"Trust in the LORD with all your heart, on your own intelligence rely not..."
A - be audible. Speak clearly, do not mumble. Speak in a way that elicits interest in your sharing.
B - be brief. A good sharing can be made in 7 minutes or less. Try to target for this. Going beyond this time, in case a particular sharing has much significant content, should be the exception. Since the overall time for sharing is limited, this affords more people the opportunity to share.
C - be Christ-centered. Do not just tell a story, however interesting it may be, but relate everything ultimately to Christ. The sharing is meant to glorify God, not just amuse or entertain people.