The one thing that you need to keep in mind is timing. Most shows will send you a show list that includes all of the brides who signed up at the show. It's important that you contact them soon, but you don't want to pounce on them like you're desperate. I'd wait until a few days after the list goes out so that you can go through and prune it.
Before the show list gets to you, though, you should have sent out an email to everyone who signed up for your business email list at the show. (If you don't have an email list, read this: Email Lists) Those are the people who were interested enough to tell you individually that they want you to contact them, so get to them quickly.
I'd send them an email the day after the show, saying that you were glad to meet them, and that if they would like more information they can go to your website. Offer a tasting appointment if you have some dates set up (you should set some dates up for a bunch of post-show appointments) and let them know when those are available. Sending them a follow-up quickly will beat the rush that they're going to get when every vendor from the show gets the full list.
When you get around to dealing with the show list, go through it and delete the people who are getting married on dates that you're not available. Delete the people who are already on your business list (you contacted them already). Delete people whose names and emails are obviously fake. Delete people who have the words "princess" or "diva" in their email addresses (that last one is optional, but I've always found it to be a good idea.)
Once you've pruned the list, send out a general email with a friendly greeting and a link to your website. Say a little bit about your business and what makes you unique. Invite them to sign up for your email list and give them a link to do so. Then hit send and don't worry about it again. Pestering people won't win you any prizes, and the people who are interested will sign up for your list.
Make sure to put something about why you're contacting them after the signature of your email. A simple "You're receiving this email because you signed up at the XYZ bridal show" is enough.
Do NOT sign people up for your email list without their permission. If they didn't tell you to it's considered spamming, and that's not good.
Finally, follow up with any vendors you met who seemed like good connections. Send them a quick email saying hi and linking to your website. Let them know that you enjoyed meeting them at the show, and that you'll be referring brides to them when you get a chance. Don't beg for referrals, just offer to send people to them.
If you have any other suggestions about wedding show follow-up, please post in the comments below!
Kara Buntin owns A Cake To Remember LLC, online cake supplies at www.acaketoremember.com and www.acaketoremember.etsy.com