From a former gunshow dealer:
Dont be afraid to ask questions and engage in limited small talk.
On the flipside, if you have no intention of buying something, dont waste time negotiating a price just to see how low you can go, then walk away.
An example, I once had a guy spend 20 minutes talking me down $15 on a cheap scope, then walks away over the sales tax....wasted 20 minutes and walked over a buck fifty sales tax....
Had another guy, an accountant, talked me down from $15 to $12 on a set of dies....then walked over sales tax...84 cents....
Have fun, enjoy the crowd watching and keep in mind, many of the actual dealers, are there to make money, you know, a living...