This post is going to be only in English due to the length of the post, if you want this in Finnish I can translate it and put it up next week.
First I have to say there is no right blush shade out there, it is mostly down to personal preferences. There is no wrong or right in makeup (even if someone might think so). I'm only talking about this post what in general suits what skintone the best.
Skintones are divided mostly on upper level to just three tones - light/fair, medium and dark. That is quite narrow and all of these have different undertones and skintones in them. For example most of the world's population falls under medium skintone. Even in light/fair skintone - to which I belong - there are a lot of different variety in there - freckles, pink undertones etc.
Easiest to remember is that the darker your skin is the darker or brighter the blush needs to be. Light-skinned need to pick up the lightest shades or least pigmented ones.
Also if you're in doubt check what your cheeks look like after a good workout - is the blush pinkish or more coral or even red.
On myself I've noticed that in summer since I don't tan my face gets a bit red (yeah, I tend to slightly burn it even through high SPF) and then I can easily get away with red blush (lightly added). So choosing a blush really depends on what works with YOUR skintone and your face.
But let's go into different skintones - from lightest to darkest.
Fair/light skin
Fair-skinned people should lean towards lighter, dewier and sheer formulas. You don't want to take dark plum blush and apply a harsh line to your cheeks (unless it's intended). Gel or cream blushes are a good choice since they can be applied lightly and they leave a nice finish to the skin that blends the colour better to your own skintone.
Colour-wise best choices are light corals, pinks and peaches or apricot (which is tad bit more orange than peach and a tiny bit darker).
Medium skin
As I said before this is the category to which most of the world's population belongs to. Good colours for people with medium skintone are those that suit the fair ones but the colour should be a bit darker or brighter. Mauves and roses look beautifully natural on medium skin. Also instead of peach or apricot go for amber colour - which is between yellow and orange in colour wheel. These colours make you look more awake and freshen up your skin.
Dark skin
People with dark skin can get away with really bright and dark colours. Don't be afraid to play around a bit. Instead of amber go for actual orange, and choose fuchsia instead of pink. Stay away from too muted or pale colours since they can wash you out.
If you have ebony dark skin you can get away with really rusty and deep reds, plums and bright oranges.
After all of this, keep in mind your own undertone. There are good articles online on how to know your undertone. If you have cool undertone stay with cooler shades like pinks and roses. If you have warm undertone stay on the peach and orange colours.
Then there is always the question - should cheeks and lips match. Of course not but keep in mind that not all colours still look good together. I've had to change lip colour after using certain blush since it would clash too badly and make my makeup look like it's all over the place.
If you want me to do a post about how to wear (placement) a blush just comment below.
What are your favourite blushes? (please mention your skintone also so people reading this can try the blush if they're the same tone).