Creating the right atmosphere
If your work is accepted, you will then need to have a place within the faire to sell it. For smaller faires and weekend festivals, this may be as simple as taping off a 10'x10' space on the site and erecting a pop-up tent. Events with a distinct historical setting may require your tent be period-appropriate, too, so contemporary materials like ripstop nylon walls, telescoping poles, and folding tables will need to be disguised to appear more authentically period.
For "hard sites" and longer seasonal events, you may need to buy, rent or build a shop on the faire grounds. If you buy or build, you will own the structure, but NOT the land it sits upon. You'll be required to make sure the structure fits in visually with existing faire buildings, and you'll be required to maintain it to city/county building codes and fire ordinances. If you rent, you may be restricted from making any changes to the building.