Hello Carolyn,
I can think of different ways:
Either notify the space editors for the space (you can find them on the people-tab of the space and sometimes on the overview-tab, too) by direct message, if you're following each other
OR mention them in a post of your content, so they get notified that way.
OR you could alert the moderators of the space and select "Recommendation to Feature Content" from the list of reasons, you want the moderators to look at the content. 
Regards,
Steffi.