Well, first of all you will need a quite big and soft blush brush and, since you have fair skin, a lighter colour of blush. Anything too bright will look unnatural. Get some blush on the brush, and then tap off the excess. Smile and apply where your cheeks are the biggest, the apples of your cheeks. Hope I helped!

first buy a color to suit you skin tone not to bright though you cant look orange. get a smooth brush (make-up brush) suck your cheeks in like a fish not to hard. then apply from the dent upwards to your cheek bone
(but when you have put the color on the brush shake the brush lightly )

GOOD LUCK