How do I make these cake ruffles?

It's hard to tell from the picture, but the ruffles look like they were piped with a large closed star tip (like a 2D but bigger).  If they are fondant or gum paste, probably just rolled into strips and coiled up like rough roses and stuck on.

You can put the dragees on before you pipe the ruffles by holding the cake in your hand at a tilt over a bowl of dragees and scoop them up with your other hand and press onto the freshly applied buttercream, as you would nuts  or crumbs.  Then place it on the cake board/base, tidy it up, and do the remaining decorating.

They don't look piped to me - I'd say they are rolled fondant/gumpaste cut into circles and folded into halves, quarters etc and stuck on
 

There are loads of tutorials online for 'scrunch' type roses

The cake is very pretty with all the ruffles.  I am sure you can learn how to make a cake just like that one!!  I am sure someone here will be able to point you to a video that will help you with this.  I will keep searching myself also to see if I can find anything. 
 

IMO, the ruffles look like the ones Marina Sousa makes in her Jeweled Cake class on Craftsy.  Hers are made of gum paste to retain shape and circle cutters.  The circle is folded not quite in half and then twisted.  You can then open the ruffle.  If you are in a position to get the class, she makes it real easy.

HI, it is exactly as JWinslow said. I watcher her class and that is what she shows.

HI, it is just like this(fondant, little g/p mixed) roll thin, cut circles , like you see, then pinch tother and use your fingers, a g/p tool , whatever to open it up some. hth

Yes, definitely fondant/gumpaste circles folded. 

I agree with everyone else that those are fondant or gumpaste circles folded in half and then in half again and then opened up. As far as the silver dragees,  I think if it was me I would make a gumpaste or fondant "ribbon" and  attatch the silver dragees to that with royal icing, melted chocolate or piping gel, and then put the ribbon on your cake.  That way you can remove the ribbon before eating the cake and not have to eat all of those dragees.  If you stick them to your buttercream, you either have to fish them out of the buttercream one at a time, or eat them, which I'm not a fan of. 

They are the wilton ruffled fantasy flowers:

http://www.wilton.com/technique/Ruffled-Fantasy-Flowers

The ones in your photo are probably made with straight up fondant.  That is why they are so thick.  If you add gumpaste to the mix you will be able to roll it out thinner.  The more gumpaste the thinner you can roll it without it drooping.  Of course the more gumpste the more brittle they will be when they dry and the harder they will be to cut through for serving.  hth

I just found this tutorial on youtube where she is making ruffles using what appears to be a large rose tip (though she doesn't specify) it's the same effect.This wouls be far less time consuming than using fondant...

http://www.youtube.com/watch?v=cRGZOqAWKMA

hi, these ruffles are actually made from fondant, these are indicated on Sharon Wee's tutorial on facebook.  They are circles cut and then ruffled up.