well you should suck your cheecks in and make like a fish face and apply a little amount of blush to the apples of your cheek, and just rub it in a little

If you want a strong cheekbone illusion, like the picture of Britney,
suck your cheeks in and get a fan or a flat brush and apply only a bit
to the brush and apply it to the part where you can see your cheekbone. Putting a bit of a highlighter on top of your apples will really make your cheeks pop. also, If you just want rosy cheeks, smile and get a kabuki or just a blush brush and put a tiny bit on the apples of your cheeks.

Smile! Then apply a little bit of blush on the apples of your cheeks, and sweep the brush upward towards your temples.

When thinking about what color to use, your skin tone is very important. Check out this chart to find your perfect color:

Hope this helps, good luck!