Dating the show
Take careful note of when the show is, and also when you must submit work for consideration in this show. These are usually two different dates! Also note the format for submitting work. Traditionally, in juried shows the artist must submit photographic slides of their work, but more and more are accepting digital files. Still, you need to make sure you submit the right format and size to be considered. Do not assume that your work is so special that they will accept whatever you choose to submit. This is not only wrong, but also insulting to the sponsoring organization. Not the way to make a good first impression.
If the show has a theme, make sure any work you submit fits that theme. Do not try to shoehorn it in. If it does not work, it does not work, no matter how much you like that particular piece. If you want to enter that show, do something else. Also, make sure it fits other criteria for this show. Some shows emphasis a single medium, such as watercolors, while others exclude certain media, like photography or collage. Submitting work that are illegible for the show not only wastes your time, but frustrated the sponsoring organization.
Nothing upsets me more than having to turn away work from an artist who has driven 40 miles because the show they are trying to enter restricts work to only a certain medium or theme. This past spring, we had to turn away some really good photographs because the spring fine arts show did not accept photography; photography is reserved for the summer show. Sadly, the artist did not re-submit the work for the summer photography show. Reading the prospectus would have save them a trip at the wrong time, and allowed them to enter the correct show.
I hope this information is helpful to you. And if there is anything else I can help with, please let me know.
I know that people who orgainize these shows really hope for a good turn out, both with submissions and people viewing the show. When you enter, mark your calendar to attend the opening. A lot of people attend these to meet the artists, so attending is important to both the show and to you.