Shoot it differently! Take photos in 3 different modes. Photos are not saved to camera roll immediately. They are kept at the bottom of the screen (see screenshot below) where you will be able to review them before saving or throwing it away. No need to hurry up, just keep shooting and decide later.
Shoot modes are:
• Steady: photo is triggered by iPhone accelerometer
• Touch: tap anywhere on the screen
• Timer: 5 or 10 seconds countdown