The key for men's jewelry is masculinity. Shiny, bright, and sparkling are very rarely used to describe anything masculine, so if you are describing a piece of jewelry with those words, you probably should avoid it.
Coin Necklace - Anna Sheffield - $245
Search for items that look worn or antiquated. They will have a more comfortable look to them and not feel flashy. Remember, you are wearing the jewelry, don't let it wear you. Whatever you choose, you want to make sure it fits into your personal style. It needs to feel comfortable and look comfortable.
Drop Down Necklace - Surface to Air - $121
Lastly and most importantly, you have to wear it with confidence. Jewelry is not for every guy. Some guys can pull it off with every look and some guys could never be taken seriously with it. You need the attitude and it needs to match your personality.
Anchor Cluster Necklace - Rogues Gallery - $220
Many guys have spent their entire lives never even trying on a men's necklace or bracelet. If that describes you, but you are thinking about giving jewelry a try, the key is to start slowly. You don't want to go from having never worn jewelry at all to loading up on necklaces and bracelets like crazy. Start with something small, maybe a leather bracelet, and make sure you are comfortable in it. From there, you can continue to experiment with other items until it becomes a regular part of your look.
Hook-Fastener Leather Bracelet - Giles & Brother - $115