You've practiced and taken many shots and you find yourself looking at your photos like they need an extra something. That's when you decide to do some editing. There are tons and tons of applications that can do this either web, computer or smart phone applications. I am guilty of over doing it but as time goes by i noticed my photos themselves were getting better in terms of eye catching. I now try to limit my editing because it takes away from the initial efforts of capturing my subject at the best possible angle. Below are some examples of my before and afters that I feel would help you see that editing should be used to make a good photo even better.
The above shot was taken using a 50mm lens, and edited with HD filter in Adobe Photoshop.
This photo came our great and almost felt as though I should not have done a edit on it, but because there a few elements in this shot that i could not ignore. The fact it was shot in during the early morning, the sun provided a great yellow effect and given the emblem is yellow, it allowed me to enhance and continue with the edit. the final pic came out great. If you want to see it in High Resolution, here if the Flickr link. This was also shot using a 50mm lens.
Completely different shot than those above. This was also shot with the 50mm lens. Here, editing is almost needed because you want to bring your some of that early fog. Notice how the light is a huge factor in this photo because of all the shadows. The colors brought out the fog and made the field more dramatic.
When you are caught between editing and not editing, stay put, do not edit your shot. The above is something I feel is almost perfect in terms of capturing everything and being satisfied with the final shot. There was nothing that editing could have done to make this a better photo. Some of your photos will look great and there won't be a need to do anything further and try and make it better. At the end of the day, if you are happy with your shot, that is all that matters.
I hope this had helped shed some light on editing and when it should be part of your photography finishing. Taking the right shot is exciting and editing should make that great shot even better.