Not talking about display, but experience and giveaways. How do you be the coolest booth in the building?
Begin by putting yourself in your target audience's shoes (aka: the shoes of the people attending the trade show.) What would surely get their interest? What types of benefits are they looking for in products/services? Are these people with a good sense or humor or are they looking for awards, approvals and things like that to verify a legit product/service in your industry? Once you understand what is attractive to your customer base, then you can start coming up with ideas.
These ideas could range from just designing an excellent exhibit space with documents and posters that display all of the information/benefits that this audience is looking for, to a social media contest/conversation with a hashtag.
Having experience with trade shows, I would definitely suggest you pre-order promo items that your audience will find interesting - if you want to be out of the box, then my suggestion would be for some sort of puzzle to be solved. Something that people would have to move around or use critical thinking skills to accomplish, and then inside could be an item of importance or something like that. Or you could even hold a contest at your booth in which different companies work in teams to compete against each other to complete a task or solve a puzzle or something like that.
Turns out this is kind of difficult to explain via writing. If you'd like more ideas or any elaboration, please contact me! You can contact me on Clarity or you can contact me through my website: www.bloominari.com (I own a marketing agency). I love helping businesses solve problems and engage their audiences, so feel free to reach out to me!