There are so many Do's and Don'ts for when you are getting married, but these specifically talk about getting measured and ordering your dress.
Don't get measured and then fight with the person ordering your dress about the size. I know it sounds strange to order a size or two larger than what you normally wear. But the designer sizes are wonky... don't take it personally if you wear a size 6 and then they ask you order a size 10... it's not you, it's them!
Don't get measured and order your dress and then get a boob job! Obviously your dress won't fit you the right way, and if you are planning on getting your boobs enhanced order your dress appropriately!
Don't not plan (That means plan!) for what undergarments you are wearing for your dress in advance. If you are wearing Spanx to the wedding, wear them for the fitting, and check and make sure the panties you want to wear with your dress, actually work.
And if you measure strange like me (Bust size 12, waist size 5, hips size 10) Order the larger of the sizes and then have it taken in... I know it stinks, but you have to do what you have to do...
That's just the start... use common sense!
You want to look beautiful and classy and amazing, not like you are going clubbing!