6. Explore the crazy-powerful new search feature -- starting with face recognition
See that blue circular icon with a magnifying glass in your main photos list? Tap it. Tap it now. Trust me.
That icon takes you to Photos' search screen, which holds some of the app's coolest and most powerful features.
At the top of the search screen, you'll see the six most frequently photographed faces from your images. On mine, for instance, I see myself, my wife, my daughter, my brother, my mom, and my friend Andrew (who evidently wormed his way into enough photos to earn a spot in my top six -- sneaky bastard!). You can also see more faces by tapping the "More" link next to the word "People."
Tap any of those faces, and you'll see all of the photos -- or at least many of them -- in which that particular person appears. And here's what's crazy: Google says the app is able to track a person's face and continue to recognize it as they age over time. So in theory, at least, the current photos of my daughter as an infant will one day be grouped together with photos of her as a young child, a teenager (eek!), and an adult.
Spot a photo where it doesn't belong? It's bound to happen every now and then (though the recognition has been pretty close to spot-on in my experience so far). If it happens to you, simply tap the menu icon at the top-right of the screen, select "Remove results," then select the photos that shouldn't be present within any person's collection.