What you need:
Main flower
Filler flowers
Floral Tape (you can get this at any craft store)
Floral Wire
Scissors
First step is to measure your head. This doesn't have to be anything precise, simply wrap the wire around your head and mark it. Once I have the general size, I like to wrap the wire around a couple times to give it some stability. Then wrap the ends around. If you want you can use some floral tape to make sure nothing is poking out.
Next start cutting the stems of your flowers. You want to leave a little bit so you can easily attach it to the crown, about two inches. Make sure if you're using roses you cut off the thorns!
Grab one of your main flowers and a smaller filler flower and tape the bottom together with the floral tape. You make several of these, amount depends on size of the flowers.
Once you have enough of the little boutonnieres, you can start laying them out. Make sure they're all facing one direction with the nicest flowers in the middle. I don't add flowers all the way around because I like being able to adjust it without crushing any!
Use little bits of wire to attach the flowers to the crown. Wrap the wire around the floral tape and the crown wire, making sure to tuck in any point parts. It may seem flimsy, but once you put it on your head it will have structure!
I made a little one for my cat, which she did not enjoy. She reminds me of Dinah from Alice in Wonderland!