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.
Choose an appropriate day and time for hosting a webinar. Look for when you will receive the most traffic. To maximize the attendee rate, experiment with different days and time slots and learn the conversion and attendee rates.
Remarketing helps bring people to your sales pages which were at the conversion stage. It targets leads which remained unconverted. Another way is to approach leads who have already register for the webinar and attended it. It will help convert these leads in to clients.
Remarketing attracts previous leads to your webinar, which helps prevents losing leads. It also increases the chances of conversions, because previous visitors provide a high potential of conversion.