What can you do with a 38 millimeter screen and two tiny buttons? A lot, it turns out, if you're willing to make some edits.

To win coveted space on the Apple Watch, brands are scaling down the apps that have succeeded on larger devices, offering minimal bells and whistles and limited functionality.

What is lost, for the most part, are enticements to buy or any sort of e-commerce. What remains are post-purchase conveniences that take advantage of the device's prime position, strapped to the user's wrist.

Target's app helps you keep track of your shopping list, but you still have to go to the store. Expedia's app makes it a cinch to track your flight, after you've bought your ticket. The next time you go to the movie theater, Fandango's app will speed you along to your seat, assuming you've bought it elsewhere.

"It became obvious to us that the most utility we could provide through a Watch app was around trips travelers had already booked — providing super-critical, relevant information before the user needs it," said Jordan Singh, Expedia head of mobile product.

But that loss of commerce isn't necessarily a disadvantage. "Would you build all the same stuff into the Watch" as you did a larger device? Singh asked. "We wouldn’t; we think it’s a very different experience."

The Expedia app provides continually updated flight information and push notifications to travelers throughout their journeys: sequentially providing departure and terminal information ahead of the trip, generating confirmation codes at the kiosk to print a boarding pass, locating the departure gate, identifying the baggage claim and displaying hotel and car-rental information.

The Fandango app is all about timing, too. Unlike the company's phone app, the watch app wasn’t designed to help customers decide which movie to see when, or to buy the ticket, said Mark Young, Fandango head of strategy and business development. The focus instead is getting the customer to the movie on time — a more natural extension of a watch's function. For example, the app provides a countdown to showtime, generates directions to the theater and displays the ticket itself, allowing users to bypass the ticketing line with an easy flash of the wrist. (All tasks the Fandango phone can perform as well, Young noted, but without requiring you to pull a device from your pocket.)

Fandango's designers focused on "packaging to optimize convenience — we have all the info compacted onto one screen," said Young. The app also features integration with Passbook (Apple’s organizer for tickets, coupons and passes) and Siri voice commands, both of which are native to the watch.

Joel Sucherman, NPR senior director of digital products, said that adapting the NPR One app, which allows users to curate news stories across NPR properties, was an exciting challenge. He echoed Young’s sentiment that the work had to focus on "thinking about how people would use the Watch.

"It’s not just 'slap the app on the Watch,’ " he said.

"Public radio seems to be an intimate experience," Sucherman said, confirming the experience of everyone who has experienced a driveway moment. The convenience of being able to control your listening queue on your wrist, Sucherman said, "felt like the right space."

In terms of engagement, it was important that the NPR One app maintain the "deep connection" NPR has between local stations and national network structure (after all, the local stations pay for programming). Toward that end, the app geolocates the user and opens with a local news anchor giving a welcome.

Sucherman said NPR is planning a "couple of campaigns" for Apple Watch. Underwriter spots will take advantage of NPR One’s voice and graphics, and, Sucherman said, they might explore extending voice-activated ads that allow users to respond by voice to "Learn more about … ?" prompts.

NPR is also running similar promotions on the editorial side, such as an audio cue in one news program asking if you’d like to learn more about, say, the TED Radio Hour. "The technology is in its infancy," Sucherman said.

Overall, Sucherman said he is excited by the possibilities.

"When we got wind that Apple was trying to establish a new category in the wearable space, it felt like they way they talked about the iPad [when it was being introduced] — there was enthusiasm for a new category," Sucherman said. "This was an opportunity not just to extend the NPR One platform, but do it in a different way."

Matthew Rothenberg contributed to this report.