I can't stress enough how important your images are. I don't mean that it's necessary to pay a pro, but if you don't provide a jury with well-lit, non-blurry, properly sized photography it won't matter how well-prepared you are for their show because you won't have the opportunity to participate. Period. A few dos and don'ts:
When in doubt, use natural, diffuse light. A mid-afternoon, south-facing windowsill, for example.
Keep the background simple. Don't use patterned fabrics as it will only detract from your work. Patterned backgrounds can work as long as they're monochromatic (i.e. grass, leaves, stone) and bright colors can be used carefully to direct the eye to the subject, but be honest with yourself when choosing the final image. If you notice the background before the work you should start over.
Most images should be of one piece of work alone. Pick your favorites and photograph them solo. Group images can be overwhelming and don't allow your work to speak as well for itself, which is the whole point of images within an application.
Don't worry about establishing scale in your images (like with a coin). If it's important to the jury process there will be a place to provide that info.
There are often image size requirements on applications. Read those carefully and follow them, otherwise juries can be faced with huge files, giant blown-out images or totally blurry ones. If you are unsure how to re-size photos, ask a tech-y friend (don't we all have at least one at this point?) or poke around online to find instructions. You don't have to buy fancy image-processing software, either -- a simple google search pointed me to this among others: http://www.gimp.org/, instructions included.
As far as the rest of the applications goes, common sense prevails. Make sure that the link to your website and etsy shops are correct, double-check all of your personal/ business contact information, and carefully read and follow any instructions for paying your application fee.
As incomplete of a means as it may seem when you're boiling down your craft for the purpose of jurying, your application must speak well for you in very short period of time. That said, keep your images simple and clear, make sure that your personal information is complete and correct and make sure that we know where to find you when we want to tell you how wonderful you are and that yes, we want you to come to our show so that we can get to know you better (and so that you can sell, sell, sell!).
Best of luck!
Here's what a couple of other crafty folks have to say about such subjects: