Send them invites for your webinars or whitepapers. Send an email regarding it, and wait for their response on it.
Guide and show attendees where they should click to earn benefits from the webinar. This will help bring more clicks to your landing page by appropriate CTA defining.
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.
? Develop great content: