It really does make a difference if your picture is sharp to start off with. I have quite a few pictures that are really not very good but have some value in terms of content. What I want to try and see is if it is possible to make something of a picture even if it isn't good.
I took some underwater pictures with a camera in an underwater case but the camera got so steamed up that I could only take a couple of pictures before the whole thing was too cloudy. This picture was taken in not great snorkelling conditions as you can see by all the bits in the water but I never really got any decent pictures so I wanted to see if I could do something with this one:
Well, it is obviously much better but not as good as it could have been if it had been sharper: