1- Wear something you are comfortable in, like your favorite pair of jeans or T-shirt, this will make you a litte more confident if you aren't sure about trying glitter and sequin :)
2- Wear something neutral.
3- If you are still not sure about wearing glitter, you can always wear it in accesories, like belts, a cute headband, scarf, socks...
4- Get glitter/sequin clothes in gold, black and silver, those colors are very easy to match.
Look how many glittery/sequin things I've found in Forever 21! and you can see here some examples on how you can style it:
Some cute accesories from Zara: