Speak with passion for what you present
If you sound uninterested in what you preach, why should your audience care?

Make relevant comments throughout the webinar
Don’t just read aloud what’s on the slides. Allow yourself to digress in moderation, but keep the digressions relevant to the webinar or your audience. A good-ole pop-culture reference or an inoffensive joke is also a good idea ;).

Do regular check-ins with your audience
Pause for a minute and ask the attendees if they understand everything you’ve covered so far. Make sure they’re comfortable sharing what they’re struggling with at this point.