|The images that always suffer from a lack of comments are the ones that are right in the middle ground. Everyone comments on the awesome shots. Some comment on the bad shots. But the middle ones, very few people say anything. So here I am to explain why I voted a 5:
The most important subject in this image is named in the title itself... the fly. However, the fly is also the least sharp of the picture. Two possibilities here: 1) You were just a tad too close and your lens couldn't quite focus on the fly, or 2) the camera caught the leaf and focused on it instead of the fly. For macros, sharpness in the subject is imperative, so really this is the only thing that, in my opinion, is keeping this image from being a better shot.
Things I do like: the fly is facing the camera. Kudos! I don't know how many images I've seen where you're looking straight down at the bug, or looking at it's rear-end. It ends up looking like its getting away. Yours has a nice angle to it as well. Again, kudos.
One other thing that could improve your score would be to get in even closer... but you may have to save that idea for some new equipment. Anyway, hopefully you had fun and I hope the comments help.