What gets my attention in order:
Colors in booth/table area- strong or bright colors get my attention every time.
Good signage- large enough to read the name as soon as the colors get my attention. If it is a smaller venue, this matters less than a large one.
Attractive company name/logo. I am not overly choosy in that I like nature-type stuff, elegant stuff, cutesy stuff, but your name and the "theme" need to sort of go together. I.E. "Betsy's Bubbles" should have bubbles on the sign, and favor cute colors. "Nancy's Naturals" should have something ... well... natural on the sign, and the colors should be from nature. "Oliver's Old Fashioned Soaps" should have perhaps a sepia toned sign with barber shop reminiscent designs.(Names are purely from my imagination, and are not representing any company whatsoever.)
Lots of product. I hate feeling like it is all picked over before I got there, and I am choosing from the dregs.
The products need to stand out against the background colors. I don't like things that fade into the scenery. If your labels/products are beige, go for a strong solid table cloth color to make the products stand out.(forest green popped into my mind)
The smell of the soap. This is always what makes me take it home. I really don't care what you call that soap, as long as I know I am not allergic to the ingredients and it smells good.