Send them invites for your webinars or whitepapers. Send an email regarding it, and wait for their response on it.
? Run a free promotional webinar:
? Send an email:
It is really difficult to get an audience to be a part of your webinar. You always need to look for a topic from your niche that is trending to be able to capture the attention of a large audience. Do some research and look for customer problems. Be relevant and informative with your webinar topic to encourage more people to attend your webinar.