Ensure that you know who is attending, what their needs are and what other attendees they are likely to benefit from speaking to.
Create a relaxed and informal atmosphere where people can feel comfortable to be themselves and do their most creative thinking and connecting.
Ensure good organisation and build up and an interesting venue.
If you have speakers, try to get great role models who can inform, inspire and entertain.
Create the feeling of making a difference and being part of something unique.
Continue to offer connections and advice where possible after the event and offer to put people in contact with those they may not have had a chance to speak to during the event.