When using the Camera app, having to tap the shutter icon on the screen can often cause camera shake or a lack of focus.
Instead, press either of the volume buttons on the side of the device to capture the shot. This lets you hold the tablet horizontally like a conventional camera, giving much more stability to take a better picture.
You can also capture a photo by pressing either of the volume buttons on the inline remote on a pair of Apple headphones. This allows you to keep the iPad steady as you don’t need to touch it. This can be particularly useful when using a tripod or leaning your device against a surface. It works wonders for initiating Time-Lapse mode.