The 1st and the 2nd image have just a bit of a lack of contrast with the colours. The red could be a bit brighter in the first image, and the darker white could be a bit more darker in the 2nd image.
3rd image: add some grey on the bottom of the clouds for more volume. And use the dark brown earth colour to do the same to the bottom of the land islands but with a rougher transition to give the earth a rough texture compared to the smooth colour transition of the cloud.
Hope I helped somehow.