See to me the key action in this is the people and that boat, so get closer. As well, the leaves up top don't add anything. Watch your highlights, I get its hard to do with digital but the majority of the sun is blowing out to pure white, if you shot RAW there should be detail to pull back. Your settings were ƒ/9.0, 1/2500, ISO 640. First drop that ISO down, its noisy, you shouldn't need to be above 400 in most situations. As well, I don't think the silhouette adds much, this is probably 1-2 stops underexposed so either push the exposure comp or drop your shutter speed.