Draw out the numbers of the year or the letters of the words "Happy New Year" on your cardboard, and use the box cutter to cut them out. Paint white glue onto the front of your numbers or letters, using the paintbrush to get a generous, even coat of glue. Working over a piece of scrap paper or a tray, shake a liberal amount of glitter onto each number, then let them dry overnight.
In the morning, shake off the excess glitter, and you're ready to string! Turn your numbers or letters over and arrange them in order. Then, use the paper tape to attach the fishing line to the backs of your numbers or letters. Make sure you leave a short tail of fishing line on either end for hanging purposes.
Once you're all taped up, you're ready to hang! Just wrap each of the end tails around a tack or nail in the wall to display your sparkly decoration.