Try to make a convincing invitation to drive registration. Don't give them a reason to feel like your invitation is a corporate "fill in the blank" form. Target a specific segment and make a personal connection, so you can retain them longer.
You can involve sponsors in your webinars to make money from sponsored ads and announcements which run in between of your webinars. It can be very beneficial when you are attracting larger audiences through your webinars.
? Develop great content: