I like that one white cloud and the background color. I also like the branches they are very distinctive. The one thing I don't like though is the sun spots.
You should have tried this in black and white with a touch more contrast, it would have looked far more dramatic. Interesting composition which unfortunately slightly suffers from lens flare. Good luck with the challenge.
the craggly old baren tree makes a good subject against the blue sky - and I like low angle shots like this. It would be better if the sun flares were not there though.