I guess it's a sad fact that the only way to learn is to do, and figure out what went wrong, or what went right.[/quote]
I dont think that's sad - I find it motivates me to do more!
As to what is 'good' - it depends on what the photo is for. Memories are important, even if aesthetically the images are weak, so a 'good' memory can make a 'good' photo. There are all sorts of perceived rules about 'good' technique and composition, colour theory etc. But, perception is everything in aesthetics! If it looks good to you then it is good! Learn what looks good to you and why, then try and do it again.
