For off-the-shoulder or strapless necklines, make sure that you have a strapless bra that will offer just the same support as your everyday lingerie, without, well, the straps. Sizing is key on this one, so you might want to walk yourself into a proper lingerie store (at least for your first purchase) to make sure that you've purchased the Goldilocks perfection of strapless bras, no tugging, adjusting, or pulling necessary.