Store your ID card in a protective sleeve. These sleeves are your best friend. Not only do they protect your card from getting scratched, crumpled or wet, they also allow you to attach your card to a lanyard or a key reel. This allows you to keep your card with you at all times and prevents those embarrassing runs back to your dorm to look for it.
Never deface your card. Do not punch holes in it, draw on it, write on it or try to change the bar code. This may result in the card scanners being unable to read your card and your being stuck outside the cafeteria looking forward to another bowl of ramen soup in your dorm instead of the pre-game buffet.
Keep your card in your wallet or hang it from a lanyard. Do not crumple or fold your card. This includes accidentally creasing it by throwing it in the bottom of your bookbag and then stuffing your 500-page literature book on top of it.
Avoid keeping your card in your pocket. Inevitably it stays there--even when you change pants. This is a good way to accidentally run your card through the wash. It's also a good way to let your ID card get scratched by keys, coins, bottle caps and other miscellaneous objects in your pocket. Your pockets do not make a good home for your ID card.
Keep your card away from magnetic fields such as those created by stereo systems and computers. Their magnetic fields can ruin the card's magnetic strip.
Keep your card away from direct sunlight, heaters, hot plates, hair dryers, curling irons and anything else that radiates heat, as this could melt your card. Producing a deformed card in your dorm will not make up for failing to produce deformed fruit flies in Basic Genetics because you couldn't get into the building.
Avoid using your ID card as a bookmark. The campus library will undoubtedly find your card in your returned volume of War and Peace, but many miserable days will have passed before they do.
Avoid placing your ID card on your food tray at the cafeteria. Although the kitchen workers may enjoy laughing at your photo when you inadvertently abandon it with your tray, you need the card more than they need the amusement.