I haven't really done a con yet but I do an annual craft fair every year and it's pretty much the same set up and everything just probably a different market [more adults with their kids type of deal since it's put on by the Girlscouts]. I found that having certain things handy and doing certain things as well, I'll list them :D Having a neat table, making sure your items are set up in a way that makes them easy to see and placed with items that are alike like categorizing basically. Setting them up in a way that draws the eye in, take a step back from your table and look at it as often as you want while setting up, if it looks good to you it will probably look good to people walking by. Have hand sanitizer with you for yourself and maybe put it on the corner or somewhere on your table where others can get some if they need and when they stop for a squirt of it that will give them a chance to pause at your table and maybe see something they like! Keep business cards in a cute little holder or bowl [or something that goes with your display!] in a place on the table where people can snag one or two when they come by. They may see something they like but are unable to get it at the moment or maybe they think someone they know would LOVE that special something on your table, people love business cards lol. Make sure they have all the info you want to share such as name, E-mail,Etsy, Facebook,Pinterest, Etc addresses on them so folks can find our shop wherever it is! I like to offer nice packaging at my table. I keep colored tissue paper and make little gift bags out of cheap brow sandwhich bags from the store that have my name on them and use funky scissors to cut the tops off to give them some pizazz. I always ask if they want their item wrapped in case they aren't ready to wear it or carry it in the pocket, or maybe they are buying it as a gift etc. DEFINITELY keep snacks under your table or somewhere near you. Being hungry in a sea of potential customers is never fun especially when they're all walking around munching haha! I like granola bars or whatever is satisfying in a fix and able to be eaten discreetly [not much is more embarrassing or awkward than a customer inquiring about an item while you are chomping on a cheeseburger lol] Take time to walk around yourself and maybe check out your neighboring booth! 9 times out of ten the people are super friendly and energized about the event just like you and you could make a friend and get some inspiration, who knows! They could also end up checking out your table and end up buying something from you or making a trade [it's happened to me and I love it :) ] It also helps relieve some possible tension if you're like me and you can get anxiety around a lot of people you don't know well. Standing up and walking around to check out the place is always great! Have a nice sign somewhere either on the front of your table or banner that is both appealing to the eye and states clearly the name of your shop and what you sell that way people can see you from across the room and say 'oh look they sell this, let's go check that out!' instead of accidentally wandering into your booth they will be able to tell ahead of time if they are interested.
Lots of small tips that you pick up on easily, all in all just enjoy yourself and have fun! The first time I made a public appearance with my shop I was so nervous and kind of over prepared [which is great lol] but I had so much fun! The more relaxed and easy going you are, the more attention you'll draw in and the more people will want to talk to you and know about what you do :) Have fun with it!