Other forms: discerningly
Discerning people pick up on subtle traits and are good judges of quality — they're the ones who can tell if your cupcakes are homemade from the finest ingredients or totally from a box mix.
Discerning is an adjective that comes from the Old French discerner, meaning to “distinguish (between), separate (by sifting)” — which makes sense, because someone with discerning tastes or a discerning eye is good at distinguishing the good from the bad and sifting out the gems from the junk. If you're an ace at picking out fabulous fabrics, accessories, and shoes when you get dressed each morning, you probably have discerning fashion sense.