David Tue submitted this image of the Grand Canyon taken with his Canon XTi at 1/50 sec, f/22, ISO 100. David is still new to DSLR photography and has done a good job. To fine tune this image, straighten the horizon and crop the greenery out of the left bottom corner. You mentioned that you are just learning to edit digital photographs, I would suggest a slight curve adjustment which will add detail to your tree. The colors are already vivid so I wouldn't do anything to the saturation but learn about Unsharpen Mask which will add a little zip to this photo. Overall this is a nice start.