I've learned some tell tale signs as to whether people are willing to chat a little bit. To be honest, I'm still working on being a little chattier :)
Anyway, I always greet people when they walk into my booth. I've found that there are usually three kinds of people:
1. I say, "Hello" and the person says, "Hi" but walks immediately out of the booth. I always feel really awkward when this happens. . .
2. I say, "Hello" and the person says, "Hi" in return but doesn't look at me they keep looking at my stuff.
3. I say, "Hello" and the person says, "Hi" in return and looks at me when they say it. Thankfully, I think most people fall into this category and these are the people who will usually chat it up. If not immediately maybe some time during their visit to the booth.
Don't worry and have fun! Even though I'm not too chatty, one of my favorite parts is meeting other people at shows. I would love to run into some chatty :)