Find an old woollen jumper. This one came from a charity shop (thrift store). Shrink it in a hot wash and you have made your own felt!
You can then use it for all sorts of projects (I made mittens out of this one as well as the phone case).
Cut off the end of a sleeve so you have a ribbed end to work with. Cut it to a bit bigger than the size of your phone.
Gather together your chosen embellishments, including a button for making a closure.
Turn the felt inside out and sew the non-ribbed end together. I used blanket stitch. Turn it back out again so you have a neatly sewn bottom to your case.
Measure out where you would like a button closure to be and sew a button hole by hand or with a machine.
Mark with a pencil where the centre of the button hole is and sew a button on to the inside of the case on the opposite side to the button hole.
Sew on your embellishments.....
And voila! Easy peasy!