For the first picture, too much PP (got purple colour cast and lack contrast), the horizon is slanted and should follow rules-of-thirds.

Second picture got purple colour cast and I think it will be better if follow rules-of-thirds.

Third picture, nice composition. But CA is very obvious.

If you want to make the sky your main subject, get it to be 2/3 of the picture. Don't do too much PP as it will do more damage than good. Saturate the blue channel a bit and increase the contrast. If you really want blue skies, use a CPL (Circular Polarizer). Do make sure the horizon is straight.

Also remember to calibrate your monitor for correct colours and contrast before doing any PP.

CA is Chromatic Abberation, aka Purple Fringing. There is nothing much can be done as this is due to the lens construction and quality.

Keep on shooting!

No comments on the pictures but I would like to know where you people bought the poker set (cloth and chips)?

Wanted to look for them to play Texas Hold'em for CNY.

Thanks for the info! Do not stop playing Texas Hold'em. It's a wonderful game!