Alpha_7,
Can I be critical here?
I do shoot sky, because I find that pattern and colour up there can be simply impressive. Also I found that is not easy to shoot sky or clouds. Not only because of high contrast, that is the smallest problem. Real difficulty is showing well known subject in new, fresh, unusual, catching, original way. Somehow similar to shooting roofs, you see
This needs being able to see composition, shape, colour pattern, detail etc., which I recon is somehow missing in your photos (but remember, it is only my personal point of view and it only depends on you how you will interpret that).
I am not saying I am much better. Propably not, considering number of shutter releases I have done and number good photos of sky I have got
But one of the best I have got is one presented below. I hope this can give you and idea what I am talking about and can help you in your quest for perfect sky
Regards,
K.Polak