Here are 2 of my perhaps a bit blunt but simply true (based on my experience) answers:

1. Hire SUPER Attractive People To Work The Booth
Based on your target market's demographics - hire people that are attractive TO THEM.
Google "convention booth models and talent".
It's not critical that everyone in the booth be a model... One or two will do.

2. Prepare a Unique and Interesting Short Demo of Your Product / Service
The beautiful people will get them into the booth - but you've gotta give them a reason to stay.
A great demo will also cause "buzz". Passers-by will stop to see what's up.
End the demo with a give-away.
A really cool give-away will also result in "buzz" that others will talk about (directing people to your booth).
Just make sure the give-away is RELEVANT to your product / service.

For more ideas - give me a call.

Good luck at the exhibition and have fun!