Nearly every time I hear there are rules for designing postcards, I discover that these rules can be broken.
That said, there are a few rules that you probably don't want to mess with. Here is #1:
The designer needs to make a connection with the audience he/she intends to reach.
This basically boils down to: "you need to understand who you're speaking to, before you speak."
Take a look at a series of postcard designs created for Poler. Poler makes outdoor gear for outdoor people -- not the outdoor type who wants to conquer the world, but for those who like enjoying the adventure.
So photographer Benji Wagner and artist Nicole Lavelle created a promotional postcard series which reflects that.
The cards were printed by Print Pinball on a thick, uncoated duplex paper that's white on one side and chipboard on the other.
There's no high gloss printing and no high impact sales pitch. Just a reminder of what any Poler customer can appreciate: that it's good to be outdoors.
Poler Postcard 1: Climb a Tree... Go Outside
Poler Postcard 2: I Feel Best When...
Poler Postcard 3: Morning Fog...
Poler Postcard 4: Afternoon Sun...