In many cases, the major mistakes you do when shooting a photo are not that easily corrected in the post processing unless you are truly skilled and very patient, the best thing you can do is pay a maximum attention when you shoot, which means considering the most important factors that affect the quality of an image, and these are light, camera settings and composition.
The challenging situations are numerous whenever you go out shooting, but here are the most common mistakes and some ways to avoid them. If you have messed up the sharpening of an image, the best option is Photoshop or any other software (you will have to settle for lower quality results though).
If motion blur is a problem you often face, try to do some math before you press the shooter. The exposure value needs to be bigger than the focal length times the size on the camera’s sensor.
Whenever you try to shoot in the dark, you will have to use a tripod unless you are interested in abstract photography. Even pressing the shooter can cause a shake that destroys the good quality of any image.
The same thing applies to sunsets and sunrises and all the low light conditions of photographing. Also, keep in mind that DOF, the depth of field, gives a great deal of contrast to an image, so try to use it properly in all the situations where it can be applied.