The Camera app on the iPhone gives you a few not-so-obvious features that let you take better, sharper photos.
When you bring your subject into view, the camera auto-focuses on whatever is in the center of the scene (in the center of the frame).
You can force the iPhone's camera to focus on a area off-center by touching the screen, on what you want to focus on.
When you're ready to take the picture, hold-down the shutter button (the one with the camera icon) for a second or so. This causes the camera to fine-tune the focus and exposure. Hold the iPhone steady and lift your finger to snap the photo.
Presto! Your photos will be sharper and crisper when you use these tips.