You can promote your webinar via social media. Post something related to your webinar continuously on social media, so your audience stays connected to your event.
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.
? Use Webinar tools:
? Offer something to attract your customers:
Tips to make your webinar more successful