Its true that companies are shifting their marketing dollars away from trade shows. However, one can still drive some real benefits by participating in some key ones for one's industry. For your participation in a trade show to be effective, its no longer enough to just set up your booth and show up on the event day. Increase awareness about the event and your participation there through email and social media tools like status updates on your linkedin profile and twitter. Encourage traffic to your booth by offering free whitepapers or trials. Get enough staff to be present to facilitate conversations and respond to questions. Use a tracking sheet to record areas of interest immediately and prioritise follow-ups.
You may also run a proactive media outreach just before the show inviting journalists to visit your booth. Help them by sharing with them all the relevant information to develop topical story angles around your offering. The published story will raise the profile of your brand. The readers (both visitors to the show as well those who couldn't attend) will also then actively seek you out to do business with you.
And, if you are happy with the response, let the organisers know that you will be willing to provide written testimonials. They will be using those actively to promote their next event which will give your organisation added visibility.