Last year the most popular camera on the photo-sharing site Flickr was Apple’s iPhone. In fact, smartphones occupied 10 of the top 20 slots (and 8 of the top 11) in a list of devices favored by the site’s users. That trend reinforces what you already know: Phones are handy for taking photos. Great shots require great timing, and for that a smartphone has two big advantages: You carry it everywhere, and you intuitively get how it works. And while smartphones are still limited by the size of their sensors and lenses, the technology improves at the pace of Moore’s Law. The new iPhone 6s boasts a 12-megapixel sensor, and LG’s new G5 Android has two lenses—one for wide angles and one that’s a narrow 78 degrees. Of course, photographing birds is different than snapping a selfie. But with these tips, you’ll be able to add your life list to your camera roll. Take Back Control The camera app on most smartphones can autofocus and even track a subject. But for more...