As soon as a person register for your webinar, send them a thank you mail and a confirmation mail. Sending this is not only good manners, but will also help get a confirmation from the registrant side.
Hold a specifically designed campaign drive for generating referrals. Satisfied customer are the best place to get more referrals for your webinar.
Follow up emails can help you connect with whom you are targeting and generate a better ROI without spending much.
? Develop great content: