The single biggest challenge I have ever encountered with shows (on whatever scale) is how to collect leads and what to do with them after you've collected them. The problem seems to start with the simple act of collecting them. There are three steps:
1. Collecting them.
2. Processing them.
3. Taking action with them.
Collecting. Whether you have a sophisticated electronic system or you just collect business cards in a fish bowl, you need to record who visited your booth. Take a step up to a form (providing a stapler and pen to your staffers) and you can add when they stopped by and the visitor's specific requirements of product and service. If you do it electroncially, consider printing out the form and collecting notes on the printout to go with the end-result electronic spreadsheet.
Processing. At the end of each day of the show, do some evaluation of each lead. Categorize them by importance--is the lead hot, medium or cool? Or do they require action now or can you hold them off with a brochure or a letter? Should you pass off the leads to the area sales rep tonight or wait until the end of the show? Can you get your telemarketing staff started on the leads before the end of the show?
Taking action. If you have a sales data base or management system (CRM or other; salesforce.com) they need to be entered and given to the appropriate sales person or executive to take action. Don't let them go cold: you've put a lot of effort into earning these leads, don't let them go to waste. Implement!
Lesson learned: collect, evaluate and take action. Rinse and repeat as necessary.