Energy!

I'm can't recall any teaching situation where I would have said afterwards, "I wish the teacher had brought a little less energy."

Fact: Listeners aren't engaged in the material to a greater extent than you are.

Amp up your energy, especially as the group size gets bigger. You can dial up and dial down your volume for emphasis, and you should. Move around. Move your arms! Make serious eye contact. Let them see your heart!

Yes, we have historical examples of people like Jonathan Edwards who preached in a monotone, and saw changed lives. That's not likely for you.

Give the Lord your best, not what you're comfortable with.