Oooh are these really from scratch as in you started with a blank layer and didn't paste anything from outside? If so they are pretty nice!
I'd like to suggest maybe giving the water on the first one a little more shine and making the clouds a little more dense and swirly! It kinda looks like Planet New Berlin but I'm not sure if that's what you were going for. If you were, then good job!
I'm not sure how I feel about the glow of the first one since it looks a teeny bit out of place (since the light seems to be coming from the front left and the glow is all around the planet as if the planet is emitting some sort of light itself). I'd suggest removing the glow and add a little more shine to the areas exposed to the sun!
Lastly, the second one is also quite nice and I like the shadows but I think it could use a little more detail (perhaps put a ring on it )