Thanks for all your examples. And for your comments on the photo itself.
Perhaps the easiest thing I have learnt is not to crop too tight. Even though the subject is the butterfly, context/surroundings can still play an important part in both telling more of the story and in aesthetics.
The part I will find most difficult is to look at the ones I prefer and try to work out what makes someone think that by doing that it makes the image more pleasing. The way of actually doing it is another matter that can be learned.