So, you made it back home from the show. You're exhausted and work has backed up in your absence. Here is where the entire investment in the show can go down the drain. Follow-up is critical. Every one of those prospects need to have follow-up. Lots of it. One contact isn't going to be enough.
First, send out a short email drip that includes a 'thanks for visiting us at the trade show.' The second should be a 'call to action' email. Send an invitation to meet via phone or in person, and add something for them to download. The download can be a whitepaper, or even just your brochure, but it is always good to attach something.
Now comes the really hard work. Contacting prospects. No one is going to just mail you revenues. You need to actively market to your trade show visitors. If some seem uninterested, put their names in a tickler file to try back in 6 months. Just be sure not to just let them drop; the situation may change in the future.
In summary, look at a trade show as a marketing event that goes beyond the time spent at a booth in some convention center. It is just a stage in a lengthy and important marketing campaign. Make sure you prepare for the show and do active follow-up afterward. Otherwise a trade show is just an expensive few days meeting lots of people you will never see again.