Promoting amateur radio can be done in a multitude of ways:
Post pictures and info of club events on both ham radio social media pages, and on your personal page, so that family, friends, and the public can see them. Of course, make sure images are not subject to copyright. You should also get permission to post images of children. It is a wise idea to NOT include names or other identification of minors.
Check out the below links for example press releases and other promotions to positively draw attention to amateur radio in your area:
Example PSA for public broadcast radio station
Example press release for newspaper