Make your event eventful.
Make it one that will make people want to come and remember afterwards.
And use it in your own marketing both before and after the event itself.
Think big. But not too big at first! Decide what you want to achieve from the event; is it to generate contacts or is it to celebrate an occassion?
An event could be a gathering of 10 people for a networking seminar or it could be a launch of a new product or service.
The planning, organisation and delivery of the event is a lot of work, but once it's over then the work doesn't stop. You then need to use the collatoral (videos, images and testimonials) from the event in your marketing to show the world what you did and how great you did it.