There are some very unique ways to wear a brooch besides wearing it traditionally on the right color of your shirt.
Wearing brooches in multiples is very popular. If you have several similar brooches, i.e. theme brooches--e.g. animals, stars, moons, cluster and space them apart. The smaller ones could surround a larger one.
Or if you have several different ones, see which ones would compliment each other in color, size, shape.
Besides wearing a brooch on shirt collar, you can wear them on blazer, sweater, dress.
If you have a skirt with a slit, a brooch or brooches can hold or close it together. A brooch can temporarily replace a missing button. If you have a blazer that has a button at the cuff, why not remove the button and affix a brooch--oh so chic!
This is one fashion accessory that can be worn with everything and is the finishing touch for any outfit you wear.