Everybody knows about the brooch on the shoulder or lapel method - what people don't always consider is all the other ways a piece of jewelry can be used to glitz up your wardrobe or make a style statement.
If you wear a scarf - put the scarf ends through the pin bar in the back and pull the pin up as high as you like - or, just pin the scarf at the fold closest to your face to bring sparkle to your eyes.
Take a favorite pin or brooch and thread a chain under the pin bar on the back and you have an instant necklace - or pin it to a velvet strip choker. The same works for clasp earrings - they make excellent accents on a chain and especially beautiful on a string of pearls (best to use imitation as the pin bar could be hard on the silk knots).
Some of the larger pins make an excellent accent on your handbag or carryall. If your handbag is leather or valuable, just pin around the purse strap where it meets the purse and you have some instant bling with no harm to the handbag.
How about your hair? A pin or brooch attached to a scrunchy makes a wonderful ponytail accent. Some pins can be attached to hair clips and worn as a slide or barette. It's a very attractive look for both short and long hair.
At your waist - take a scarf and pin at an angle at your waist. If you have a side-tie shirt, put that pin right in the knot. Take an old and loved belt and attach (by magic?) a pin where the buckle was. This has worked for me occasionally with my older and softer leather belts. Really amps up a pair of jeans and a t-shirt.
More ideas coming.