Nowadays, every show attendee is vital, so it is particularly important to reduce the number of no-shows. Increasing the verification rate from 50% to 60% for a 6000-registered/3000-verified attendance show means 600 more bodies on the floor. Here are some tips on how to do this:
Have a separate promotion plan that deals with motivating preregistered attendees to actually show up. For example, send regular e-mail updates which both reconfirm existing and articulate new reasons to come.
Create an event at the last minute that addresses a very current concern of your attendees. For example, a free panel session on "Widget Sales to Europe Post Iraq." Then communicate this to all preregistrants.
Bribe exhibits-only preregistrants with a free pass to a single paid seminar or other conference session. But you must communicate this preshow so it becomes a motivation to come. Either put the pass in the badge package that is mailed out or e-mail a printable version.
If you reward others (exhibitors, associations) for generating attendance, only pay up for attendees who actually come to the show.
Promote right up to the very end. Last-minute registrations verify at a much higher rate.