You’re Not Cleaning Your Camera Lenses
This might seem obvious, but when was the last time you actually cleaned your iPhone’s cameras? If you want to try to take better pictures, you need to make sure your cameras are clean and that they don’t have any scratches on them.
Using a soft cloth and gently wiping your iPhone’s cameras will do the trick. Be careful with using water or any liquids unless you know your iPhone is water-resistant.