Your Booth Display
Start by looking at other vendors' displays for ideas. You can find samples of booth setups all over flickr.com, search for "booth shot" or "craft booth". If possible, attend some craft shows and pay attention to the displays of booths selling the types of crafts you make. Take notes, talk to vendors... but ask before taking photos, artists are touchy about that. Start with a few useful display pieces and assess after every show. As you make more things and do more shows, you will find the best ways to display your wares.
Walls or Tables
For my clothing, I use steel gridwall panels from a store supply place (another good source of ideas). They cost between $15-$20 each and come in different sizes and finishes. I like how flexible they are, how they use the space efficiently, offer tons of accessory options (hang rails, baskets, shelves, etc), and can hold a lot of weight. I would recommend walls for just about anything, even if you are a table user. They are a great way to use your vertical space. There are plenty of lighter and cheaper options like lattice and pegboard. Or fancier options like art panels.
For all the things you can't hang on walls, it's tables or shelves for you. My main advice on this subject is to use as much of your space as possible. As I discussed in my previous post, don't forget your vertical space! Use varied levels of shelves, pedestals, racks and boxes. Whatever you do, please PLEASE I implore you, avoid laying all your goods flat on a table. Boooring! And hard to see walking by the booth. Do anything you can to add levels and interest to your table displays. The big thing here is that the shopper walking by in a crowd can easily see what you have for sale.
Keep it Clean
The main idea around your booth display is to show your work as clearly as possible. Try to balance your display between too cluttered and too sparse. You want to look full, but not messy or overwhelming. Any extra supplies, boxes, personal items should be tucked away as much as possible. All eyes should be on your beautiful goods.
Please, puh-leeez, hang fabric backdrops to block out background clutter. As you look around at other booth displays, notice how many do not do this. It's really hard to see what's going on in there! In a pinch, the white walls that come with your canopy are okay, if you have lots of colorful items in front of them...but colored fabric looks so much nicer. I made my booth curtains out of cotton muslin which I dyed light purple. I sewed a casing at the top and bottom, and I run long bungees through them to attach to the canopy (I also added button holes at the center points for zip ties, to prevent sagging). If sewing isn't your thing, you can just clip and drape table cloths or big pieces of fabric onto the plain white walls. Trust me, it makes a huge difference.
If you use tables, make sure the table cloth reaches the ground. You will want to store things under there and nobody wants to see your piles.
Yes, You Need a Canopy
If you are doing outdoor fairs at all, you will definitely want a canopy. You'll quickly realize the benefit of shade, shelter from drizzle, and a more pro way to mark your space. It's also essential for hanging curtains, banners, and products for display. Of course, at first when money is tight and the future uncertain... a cheapo tent is fine. I think my very first one cost $50. There are draw backs from the cheapo tent of course. Some are not that easy to put up, may have odd angles, and most are not meant to hold much weight. But overall, it can get the job done for the short term.
If you plan on long term selling, you will need to invest in a nice canopy. I have only used EZups and they have served me very well. I hang and strap lots of weight to mine, with no problems whatsoever, even in wind. AND I can put it up all by myself in less than 10 minutes. It cost me around $250 including the walls and carry bag, and has lasted for years. You can spend a lot more on fancier digs, but I wouldn't spend less if I were you. Beware! All canopies are not created equal! Here is one vendor's review of the Caravan canopies sold at Costco, which are about the same price. Do your homework and figure out the best canopy for your needs and price range.
There are countless ways to lay out your racks and tables within your booth. Sometimes it will depend on what booths are next to you and other on-site factors. I try to figure out my layout ahead of time as much as possible, to avoid pre-show freakouts and time loss. I use Word to create a top view sized to scale, then print it out for reference. Before your first show, I suggest setting up a trial run in your yard. You'll be able to take your time moving stuff around, make sure you have everything you need (tools, fasteners, etc), and really work out the kinks. Believe me, you'll sleep much better knowing you have a good plan.
Don't forget to factor in your sitting place in the booth. You should plan to be inside your official booth area (usually 10ft x 10ft), not every space has room to sit behind or to the side. My experience has been that many people don't like to enter a booth where the artist is sitting at the entrance. Some folks want to chat and meet you, some want to shop quietly and avoid your gaze. Give them a choice if you can.
Finally, walk by your booth as a customer. Can you tell what is being sold easily? Does it look pretty and inviting? Clean and uncluttered? Is there room for more than 2 people to shop at a time?
A Few More Tips
Get a sign of some kind with your business name, even if it's just printed from your computer. A large banner is ideal, which can be attached to the top front or back wall of your canopy.
Consider floor coverings. Shows on grass or indoor floors are great... but often a show is in an oily parking lot or a dusty field full of potholes. Carpets or mats create a nice finished 'store' look for your booth, and also a pleasant walking surface for your customers.
If you have a small amount of inventory, figure out how to spread it out a little. Use props if you have room... like a mannequin, tree branch, or something that shows your work in action (ie, a small table setting for your pottery or woven place mats).
Have something to give out. People who are interested in your work will want more information to take with them. Have a card or flyer ready with your contact info and where to find your work after the show. Mine are printed from my computer, 1/4 page card stock. One side has my upcoming shows, web site, name, contact info. The other side has a small photo of my work and a bit about who I am and what I do.
Have fun!! The most important tip I can give you is to relax and enjoy your day in the sun. Admire your hard work and make notes for next time. Every show is a learning opportunity and your booth will change and evolve over time. Enjoy the process!