Draw your picture on paper first, you could just google a picture (Etsy is a great source) but creating your own would make the brooch unique and most importantly it has been truly designed by you.
You could draw a doll, a cuckoo-clock, a gnome... you name it.
Get your fabric scraps and pick your desired piece it shouldn't be that colourfull or too jazzy.
Fold in half. Draw the outer shape of your drawing on one side of the fabric.
cut out using a seam allowance of 0,5cm
Put right sides together and start to handstitch at one side of the buttom al around to the other side but leave an opening at the bottom.
Turn inside out and embroider eyes, paws, ears or whatever it is you have drawn.
use fiber fill for stuffing (you could also use leftover yarn or scrap fabric). Sew closed.
Take a small button preferably in the same colour as your fabric and glue it onto the brooch with a gluegun or second-glue. Now take your pin and glue it onto the button.