Spanx really do make that much of a difference.
Spanx come in a million different styles for all your shaping needs but below are my three faves:
1. Power Panties - I love these with skirts, especially the pencil skirts

Spanx Power Panties, $30
2. Higher Power - for a dress, a Power Panty will cut you in your middle and still make you look lumpy. You need a higher cut to come away sleek and smooth under a dress. Higher Power is perfect for all your dress needs.

Spanx Higher Power, $36
3. Hide&Sleek Hi-Rise Panty - When I said Higher Power was perfect for all your dress needs I lied. I know, I'm sorry. For a shorter dress, the shorts on your Higher Power will show and that is totes embarassing. For all your shorter dress needs, I suggest the Hide & Sleek Hi-Rise Panty.
Spanx Hide & Sleek, $42Try them. I'm serious. Just buy one pair. Put on a dress. And you will thank me forever. I'm serious. I've made quite a few Spanx converts. Once you go Spanx, you'll never go back. Okay, actually you will, because they're not exactly sexy and you might need something cuter for certain occasions... Okay, that's as much as I'll say about that ;)
And there you have it, all the EWP Essentials!