Dare we say core is the new cleavage? There is no shortage of cutouts, crop tops and sheer paneling on the red carpet. To pull off such a look, celebrity trainer Jason Wimberly (who has worked with Alysia Reiner), says you should focus on your tummy. "Skip regular crunches or sit-ups and instead opt for twisting bicycles and rotating low planks," he advises. "Not only does the transverse movement make your waist smaller, but it can accentuate your serratus anterior, the small finger-like muscles flanking your midriff." Zeroing in on that area gives the illusion of a tight six pack, even if you're not there yet.