First I would like to say that I do like this photo. With just a little work it could be really great.
Exposure: This is a little hot. Notice how the blue in the sky is a little washed out? If the exposure was a little bit darker you would have had a much deeper blue in the sky and a deeper green in the leaves. Not to mention that leaf to the right is completely blown out. As well as the tops of the berries. If you shot this raw, you might try decreasing the exposure.
Composition: Pretty good. The diagonals are a good idea. This doesn't really follow the rule of thirds. The diagonal is going right down the center of the frame. You could easily fix this with a crop I'm sure.
Processing: Pretty good job. I think you could have boosted the saturation a little. You might also be able to help this pic by decreasing the brightness.
I like the strong forms of the berries, and use of shape and line in the leaves and twig, but could have moved out to relax the composition more and make it a little about the berries and let them become simply an interseting decoration on the branch.
I like your subject matter and composition. For me, had that one leaf in the background (bottom) not been there, I would have scored this photo higher.