Many people will advise you to select a gown based on your figure type. This is good information and you will want to consider it, as well as your own personal style.
But if you are petite, and have your heart set on a large ball gown, then go ahead and buy it despite advice from "experts." It's your special day, and your special gown.
Some Standard Suggestions
Petite
A sheath, a-line dress, or empire gown will make you look taller. Avoid gowns with full skirts.
Tall
Everything will look good on you--sheaths, empires, a-lines, and ball gowns.
Full-Figured
A ball gown with a basque waist will have a slimming effect. Avoid wearing tight, slinky sheaths.
Small-Chested
A ball gown with a full skirt will give you a more of an hourglass figure
Large-Chested
A gown with a simple fitted bodice (avoid heavy beadwork) will draw more attention to your face.
Trying On Your Gown
While trying on gowns, it's important to take each one that you like on a "test drive." Move your arms around, especially over your head. You want to be comfortable dancing with your husband, throwing your bouquet, and hugging your guests.
Try to sit down in your gown, making sure it is comfortable at your bust line and waist. Some gowns, when bustled up, make sitting uncomfortable. You might want to drape the train over the back of a chair, and bustle it later.
Walk around in the gown, making sure that it is not too tight at the hips, or so full that you will be knocking things over.
Before Visiting the Boutique
Keep in mind when planning to go to an expensive bridal boutique, that many salespeople are working on a commission. You may plan to borrow your best friend's shoes, veil, and even crinoline, but they will try to sell you all of these things and more.
When you make your appointment, request that you be allowed to bring these things into their store to try on with the dress. If they refuse or seem indignant, you might want to take your business elsewhere. Shopping for your bridal gown should be the happiest part of your wedding preparations.