When mistakes inevitably occur, use them to get better.
One way photographers can do this is by researching older images in their catalog. The camera settings are often stored in the image data. If a picture is blurry, take note of the shutter speed used. If something is too dark, could a higher ISO have helped? What about the depth of field and white balance? No matter where you're at in your career, you can always learn and grow.
It's difficult to predict when or where a great photo opportunity will arise. Only by heading out with your camera often will your percentage of keepers improve. Perfection is never the goal; simply doing your best is.