Make fonts large enough to be easily read and buttons large enough to be easily clicked on. Test it out. Ask friends and colleagues to test-drive your website for usability. Use this fact to improve the value of both your live and online trade shows. Make it clear how to navigate your site.
Online users expect to see a navigation bar to the left of the screen.
Make all links easy to read and find on each page. Label each section of your website logically and place information in categories where attendees and exhibitors are likely to look for them. It offers instant gratification and is more efficient for everyone. You are likely to lose some potential customers if you ask them to phone, fax or write in to register. If possible, also give the option to pay online.