This is assuming you already know what to do with business cards. There have been tips already focusing on what to do with business cards to make them look professional even if the owners are not. To make them appear interesting to make people not throw them away the minute they are put in their hands.
This is about what not to do with business cards.
Do not print prints smaller than an ant. You may have the good fortune of having a great sight but others are not that fortunate. Take those into consideration and give them something they can read.
Do not choose colors that clash with each other. Think back into your school days and you will realize that in one way or another, you have been taught about the color wheel and about what colors partners with which.
Do not use someone else’s business card. Handwriting your information on someone’s business card is amateurish and makes you look too cheap or poor not to afford one for your own. Once is acceptable but certainly not twice.
Do not print out the wrong information. Whether typographically or innocently, there is no excuse for sending out misleading and otherwise wrong information about you. Checking them out before printing is an easy task compared to having to print and pay over again.
Do not print your business card in large-format style. Your card may look unique this way but it would not fit in the filing system that people have. Do not think that they would make their filers bigger just to keep your card. Stick to the standard size.
Do not print important information on the inside or at the back of a folded business card. People may want to contact you instantly, and they want to be done with just a quick glance at your card. Business card is not a game of hide-and-seek. It is more like to seek and seek.
Do not print on thin materials. Just shows how cheap you are by using the cheapest paper there is. Besides, they will not be able to withhold the environmental factors to which they are exposed to. A drop of rain would melt them easily.
Do not chew bubble gum while giving out your business cards. Your cards may appear all the appearance of a professional company or business, but not you. The moment they chance upon your card in the future, they would remember you looking smug as a street by-stander.