A well defined call to action should be the special ingredient in your webinar, says Ellie Mirman, head of small and mid-size business marketing at Hubspot, a marketing software company based in Cambridge, Mass.

“People underestimate the power of asking others to do something,” Mirman says. “You’ve engaged them and you want to take advantage of that and given them something to do next. But many don’t know what that next step is.”

A properly defined call to action should not only help build your credibility as an expert, Mirman says, but also can serve as a marketing tool for your expertise.

Says Mirman: “[It] should answer the question, ‘How can I use [the webinar] to promote my skills more broadly?'”

Mirman offers the following tips on creating a call to action:

> Spread the word
Tell your audience to share your comments online or over their social networks.

“Being clear about what and where to post things can really work,” Mirman says. So, set up your own Twitter hashtag or whatever you think is best suited to your message.

> Answer the question “What’s in it for me?”
Try to illustrate clearly why someone should be doing what you are asking him or her to do. If you want your audience to complete a post-webinar survey or to visit your website for more information, be sure to explain how they will benefit.

> Open the floor
Having a bit of time blocked out to field questions or get feedback from your audience will help ensure you have an engaging webinar.

Consider inviting questions at the end of a subtopic to make sure everyone is clear on what has been discussed. Just like in the real world, an engaged audience is far more likely to listen and respond to your call to action than a disengaged one.

> Rinse, repeat
Stating your call to action is just the first step. It shouldn’t be the only time you explain what you want your audience to do.

Remember when your mother told you to wash your hands before dinner? The reason it likely has stuck with you is because she repeated it ad nauseam. You should do the same with your webinar: feature your call to action prominently on your blog or website before and after the webinar.

To make sure the point really hits home, don’t shy away from repeating the call to action several times during your broadcast: just before closing the seminar and in any follow-up materials you send to registrants.

This is the third article in an occasional series on how to develop your own webinar. Next: The post-event checklist.