At the end of the day, the more you're able to hold the hand of your event attendees before, during and after an event, the more likely your attendees will remember the event as the best experience ever.
This is easier said than done as event plans change over and over again. In addition to core event logistics (site visits, hotels, catering options, tickets, appearances, etc), you are also trying to manage and update multiple versions of run-of-shows unique to different groups of attendees or specific attendees you invited to the event.
With this said, beyond sending initial invites to all of your attendees, there are additional touch points you should consider that will dramatically increase the perceived value of the event you are hosting.
Welcome Your Event Attendees
You should generate and send all of your event attendees a pre-event welcome message that lets them know you are looking forward to seeing them. You can include important reminders as they prepare for their travels. You can ask one of the sports or entertainment celebrities, that your attendees are scheduled to meet at the event, to record a video that you can include in the welcome message.
Provide Your Event Attendees Real-Time Agendas and Venue Information
You should be able to create a master run-of-show and send unique versions to groups of attendees or specific attendees. You should also be able to make changes on-the-spot to your run-of-show for groups of attendees or specific attendees. As soon as you make updates, your attendees should be able to instantly view an updated version of their specific event agenda on their mobile device. You should also provide all of your attendees with a way to access and view venue maps, parking maps, activity dress codes, transportation updates, etc, all from their mobile device, anytime throughout the event.
Automate the Check-In Process
You should be able to easily check-in your attendees to an event upon arrival using tablets, efficiently moving them through the line, reminding them of important information regarding their stay and capturing additional information from them on the fly.
Send Your Attendees Updates and Notifications Throughout the Event
You should be able to quickly send instant mobile notifications to your attendees throughout the event, when they are scattered about the venue, making them aware of schedule changes and upcoming activities, checking-in to make sure all is well or simply letting them know you are looking forward to seeing them at the next scheduled function.
Solicit Feedback From Your Attendees After the Event
You should be able to easily generate and send all of your event attendees a post-event communication that thanks them for attending, showcases photos and videos and includes a post-event survey that asks for their feedback and suggestions.
Your event attendees should be in-the-know at all times. The trick is being able to consistently hold their hands throughout the life of the event, while you're busy planning the event as well as while you're onsite managing the event.