I really enjoy using MAC's Sheertone Blushes, at least, the two that I have. I have tried many blushes that immediately turned my cheeks bright pink, and to me, this look seemed very tacky. This bright pink look made it seem like I was wearing makeup, and lots of it, while the look I was actually trying to achieve was one of natural beauty. Going for natural beauty meant that my makeup must match what I look like regularly, as much as possible.
In order to make my blush seem as natural as possible, I tried to do something exerting, and afterward took a look in the mirror. The color in my cheeks, the pinkish red color, was what I would try to emulate with my blush. Trying to match this color in my cheeks, I came across two blushes in MAC's Sheertone line: Pinch Me, and Sunbasque. They are shown below, in that order.
The reason why I chose MAC's Sheertone line was because the colors are build-able. The first application is very light, almost invisible. From there, you can build up to the color intensity that you would like. To me, making sure that the color is subtle makes it seem the most natural. And in my opinion, because the mixture of these two blushes closely matches the natural color in my cheeks, it makes me look more vibrant and healthy.
I suggest that you try my method out, and I would highly recommend you give MAC's Sheertone line a go while you're at it, because truly, the subtle cheeks look the best. If you are interested in acquiring a blush in MAC's Sheertone line, these are available at www.MacCosmetics.com for $18.50. I hope you are successful at finding your cheek color, and keep it subtle. Good luck!