Patience is key! I agree with everyone above- shorter lengths and thread conditioner if you find there to be too much snag or fraying.
Also, test different brands to find what you like.
DMC Metallic is HORRIBLE! No one likes it!
Some people hate Kreinik, others love it. Go for #4 braid for Kreinik. Try Petite Treasure Braid if you don't like Kreinik.
Take it slow and be patient and it will turn out beautiful.
When I use metallic threads I cut into 12-inch sections. If it starts to fray moisten just slightly with your fingertips or a thread conditioner. Metallic threads can kink so be patient. If the metallic thread is for just a few stitches complete all the regular thread stitching first then stitch the metallic thread and last the backstitches.
Kreinik, very fine thread - i guess it is nr4... thread conditioner and do not use long lenghts, use a chenille needle - metallic threads are a pain in the a..!!!