Events are fun, social things. 
The best way to make sure they're successful is to hype them up and get people excited about them. You don't really need to use discord to do so but it is helpful to do so.
It's also helpful to try to recruit people to help you hype up and promote your event. There are a few people that you can find either in game or in the discord that have experience with getting people to take part in events.