Hi there
one of the ways you can decorate a stall is by the use of embroidered runners. You have a plain coloured cloth covering the table then break it up with a contrasting colour runner this also mean you don't have to have different large tablecloths, just keep that a natural colour and just change the runner colours to suit the theme I did a set for a friend of mind Scorch Pyrography
http://www.scorchpyro.co.uk/ (bit of a shamless plug for my friend lol) her dragon logo i put on two runners like the ones below and then did her a central square piece with the dragon and her stall name all of which hung over the front of her stall. the nice thing about using runners is that you can also hang them up the sides of your stall and use them to decorated in lots of ways
here is a pic of some that I made to give you an idea ...
Sam