Make the event as casual or as formal as you like it. I prefer casual shows because Im not one for a lot of planning or high pressure sales. So, the few shows Ive done have been very low key cookies, punch, and a few hours of conversation while my jewelry was spread out on the dining room or coffee table. I usually had the shows during the Christmas season. I didnt spend a lot of prep time or stress over sales. Instead, I chatted with friends and still managed to earn a few hundred dollars for only a few hours of my time.
For the more adventurous, however, I have to say Ive heard a number of encouraging reports from fellow jewelry makers on the forum who have run more organized shows and acquired a phenomenal amount of sales. If you have a knack for selling and dealing with people, you could do very well, so a more formal setting may be better depending on your personality.

