I am thinking about print ads — specifically using white space in print ads.
White space is critically important, especially in a cluttered world.
Here is a good paragraph I found on NetMechanic summarizing proper and improper white space.
A page with too little white space makes visitors feel uncomfortable because the page seems cluttered and hard to read. Visitors quickly get overwhelmed and move on to a more welcoming site. In contrast, pages with too much white space seem empty, as if there’s not enough content to fill the page. Visitors may wonder: "why bother with this?" and go somewhere else.
Reminder
As you’ll see below, white space doesn’t have to be white.
Example
The company that comes to mind for me, in terms of properly using white space in advertising, is Apple. Apple’s print and TV ads are often loaded with white space to allow people to focus on the product’s design and the message.
Below are some examples of Apple’s ads featuring a good use of white space.