The main reason I go to the annual EDUCAUSE conference  is to spend quality time with the educational technology vendors on the exhibitor floor. You can see an interactive map of all the companies signed up for a vendor booth at this link. 
After countless trips to big educational technology conferences like EDUCAUSE (working sometimes on the vendor side of the booth), I've developed a few simple pieces of advice to companies:
1. Flood the Zone: Your company should bring as many people to EDUCAUSE as possible. Your best marketing dollars are spent by bringing as many employees as possible to the conferences to meet and chat with current and potential customers. If the choice is between a bigger, fancier booth and bringing more people - then always go with the people! Sure ... you need to give your folks some practice and advice in interacting with customers. And you want to schedule rotations that give employees staffing the booth plenty of time to wander the exhibition floor on their own, as well as insure that you have an excess of employees eager to engage attendees in conversation.
We want to talk with your developers, project managers, product leads, designers, testers, and directors - as well as your sales team. Having technical people staffing the booth ready to chat, and having them clearly identified as such with name tags that list their jobs at your company, is essential for building trust. Getting your developers and coders out to meet customers is a win-win. It shows a level of trust in your employees and a commitment to a set of shared company goals. This will also improve your products and services as developers and product managers can learn directly from existing and potential customers what they are looking for and what can be improved.
2. Be Egalitarian: It's always a big turn-off to have some company people at your booth in company golf shirts while others are wearing suits. Everyone should be dressed in golf shirts, and everyone should be equal in terms of being able to engage with customers. Your developer, system engineer, and junior project manager should be able to speak for your company and products with the same authority as your business development, sales, and senior management people. Give your employees as much information as you can about your company and your products and empower them to have honest conversations. The more we can relate to your employees as real people, and real people who are willing to talk about shortcomings in their own products, the stronger the bond of trust will be.
3. Build Relationships: The most important goal of your companies participation at a conference should be to build and strengthen relationships with your existing and potential user base. If the goal is articulated to everyone staffing the booth and the conference that relationships are the goal, not sales or leads etc., then the dynamic of the conversations will change. Relationship building takes time. Figure out how to schedule one-on-one sit-downs in quiet places (if your booth is too small). Work with your team to learn the art of active listening and the benefits of authentic conversation and give-and-take. Your best sales force will not be people who work for your company but the attendees who will spread your message.
My hope is that some companies will read this post in time to think about planning your November EDUCAUSE conference (and maybe push to have more folks from the office attend!).
What advice would you give to vendors?