NARS products in general have a reputation for being pigmented, and in the case of your blush, that means you may need to apply with a light hand. Some people (who prefer to leave nothing to chance) apply with a skunk brush — a.k.a. highlighting brush, duo-fiber brush. The white bristles are less dense, which means the brush will apply your blush more diffusely, giving you a softer wash of color.
Please forgive my complicated descriptions (even NARS’s website has difficulty describing these). Sertao is a very brown peach (or apricot brown? Yellow/orange brown?). Luster is peach-pink-gold with an emphasis on the peach.
Madly is terracotta peach brown. It looks slightly different in different photos, and I’ve heard that it looks different on different peoples’ cheeks. It’s rosier than Sertao; slightly rosier and sparkly compared to Zen; much more brown than Silvana.
Lovejoy is a red-brown, or cranberry-brown, with gold iridescent sparkles. All of today’s blushes are sparkly (and they have been built up to their maximum “color volume” to best show the differences between them). NARS blushes are all $25.