In order to understand what your postcard printing needs to accomplish you need to first understand how postcards work as promotion devices.
Looking at the postcard itself, a postcard is obviously small & only three sided. Given the small size, the message you put on it naturally has to be small as well. If you start to get plenty of points you need to make then the postcard is not going to be right for you.
The size also means you might have a delicate balance between images & text. All promotion needs strong images in order to do the best job, & this is certainly true for postcards. However, if you start taking up much space for images than you are not going to have as much space for text, limiting even further, what you can say.
Therefore, to make a postcard do the best job possible you will often require having a short message. This might be an invitation to come in to your store & a declaration about an upcoming sale with a few brief details about it. That way you can use as much space as you require for the picture while still have a strong message.
Using this approach, you get a list of names & addresses & send your promotion directly to people. This form of promotion works well with a postcard because a full color postcard is going to grab the eye from a pile of mail, & you’re making sure that your promotion gets directly in to a person’s hands.
Now, the primary thing to think about with postcards is often going to be distribution. Unlike most other forms of promotion, postcard printing is often tied to a specific means of getting it to the customers. This is direct mail promotion.
The cost for printing postcards in bulk is cheap, along with the mailing costs for them, meaning you do not must break your budget by using this style of promotion.
This is not the only way to make use of postcards, merely the most recognized form. Postcards are by nature meant to be sent through the mail, so it is not surprising that this would be the most selected process for getting your postcards to your customers.
My point is not to say exactly what you ought to do, but to give you a feel for what a postcard is meant for, & how they are typically used. Now it is up to you to figure out how to make them work best for your business.
However, if you have a strong picture & clear message with your postcards you can still hand them out at your store like flyers, or have a stack of them for people to take similar to business cards. The select will always be yours, & your business or your area might naturally have a more unique & favorable process for delivering promotion material.