If you are on an iPhone, shoot in Live Mode (this is called Top Shot on Android, and follows the same principles). When you shoot in Live Mode, it actually takes a 1.5 second video clip and not one still photo.
In addition to taking at least 4 photos, shooting in Live Mode will also help ensure you capture the moment without any blinking/awkward expressions. Some Android phones have this option too, it is called a motion stills photo.
To turn Live Mode on, open your camera and on the top right corner, make sure you see the circle. If there is a line through, it means Live Mode is disabled.
See how for both iPhone and Android devices in the video and diagrams below:
[ Device Timestamps: iPhone starts at 0:00, Android starts at 0:23 ]