When you buy a nice collared shirt, they often come with plastic or cardboard collar stays. These are small pointed inserts that fit into a pocket in the corner of the collars, ensuring that the collar is always straight. Unfortunately, these collar stays often get lost or put through the washing machine, never to be found again. If you're one short of a matching set, you can make your own collar stay with a few basic materials.
Lay a plastic gift card on a clean work surface. Lay out a single collar stay on top of the gift card, aligning the side of the collar stay with the long side of the card.
Trace the perimeter of the collar stay onto the card using a permanent marker. Move the collar stay down the card and trace it again, repeating the process until you get as many collar stays out of one card as possible.
Cut out the collar stays from the gift card using scissors, cutting along the perimeter of the permanent marker lines.
You can also make collar stays from old credit cards, and even heavy-stock paper.