A successful event requires attendees to show up, or it won't reach its full potential. You will have to promote your event in a way that makes sense to your topic and approach.
The most cost-effective way is to use a large variety of online services that are available and to talk about the event.
This is the best way to increase the discoverability of your event. Meetup provides the following:
In some circumstances, it is worth setting up one or more accounts on social media for promoting and corresponding as the event identity. In technical circles, it is especially popular to use Twitter as a way to create awareness about events. SSW uses a combination of X, Facebook, LinkedIn, and Instagram to promote our events, that way we have a much larger and diverse audience to draw from.
Tip: Get your staff to tweet at events and to re-tweet your events to help reach a larger audience!
Don't underestimate the power of one friend or colleague telling another. DDD Melbourne sold out in 10 hours with almost no promotion except for Twitter and Word of Mouth. If you are creating a recurring event, Word of Mouth becomes extremely important as past experiences flow through the grapevine.