The very first impression I had of this photo is that of the refreshing and clean feeling you would get after a rain storm. In that regard, you have certainly successfully captured such feeling, as well as the very essence of nature.
The color and the contrast or lack there of makes this photo very relaxing to look at. I especially like the blue tone in the back ground, it breaks away from the usual green and black combination of water drop photos.
Speaking on a technique level, you have done VERY well with the equipment you have. Although you should try to focus the water drop whether than the leaf.
Originality speaking, it's not the first rain drop on a leaf photo I've ever seen, and it won't be the last. However, every photo is unique in it's own way, so don't be discouraged just because other people has done the same thing. But I would encourage you to become more original as to what you do with water drops. I'm sure whatever it is you come up with will be entertaining to look at.
In the end, I like this photo very much. And look forward to whatever you have coming next. And good luck with it.
I like the composition of this photograph. There is a nice balance between dark and light and color in the background. The subject is placed very nicely the frame, as well. You may have wanted to try a landscape layout as well, but I still think the portrait layout is very effective. The focus and depth of field are perfect, I think. The way the water droplet is slightly out of focus makes it look very soft. I prefer the focus more solidly on the leaf as it is here, which brings out the texture of the leaf. The size and position of the droplet makes it looks as if it's just about to drip off, giving an image that might otherwise be a little cliche a good amount of potential energy.
I'm not too fond about all the lightning and colour techniques of photoprahing since I only try to capture what I think looks beautiful in that very moment, but I kind of think that this, the way you are taking pictures, is kind of how it has to be. I like how you set the focus and the colours are just amazing. Also counts for the rest of your pictures!