The Apple Store app
In Apple's iOS Apple Store app, it says, "Pick your favorite models before pre-order.... Choose your favorites by clicking the heart icon next to those models." That way, you can compare them and be ready for the pre-order process. Here's how to do it.
This is another bit of genius from Apple. By selecting your top candidates, Apple gets real-world feedback on what customers are thinking weeks before the April 24 ship date. And it'll probably help you step through the pre-order process faster as well.
1. Launch the Apple Store app on your iPhone or iPad and click on the "Shop" button at the bottom. You'll see an array of Apple's product lines. Tap the Apple Watch icon.
2. Next, from the text list, select the Apple Watch you're interested in. This example uses the stainless steel Apple Watch.
3. At the top right hand corner, tap on "View Pricing."
4. Scroll right and left until you see a candidate watch that you like. Tap the price below the watch. (You'll be able to repeat this process for several watches.)
5. At the top right, you'll see an outline of a heart. Tap it, and it will turn solid blue. (You may have to select a band size before the heart is tappable.)
Now you can tap the button on the top left, in this example, "Apple Watch" and repeat the process for some other candidates.
You've successfully hearted your favorite Apple Watches, and you'll be ready for a final comparison and selection at pre-order.