Paint Tool Sai

These
https://s25.postimg.cc/fbom0ogq7/image.png
Take note that you can EASILY change the time of day with a bit of touch ups uwu I'll show an example at the end~!

First, get your backdrop ready. I did a simple blue with a darker blue at the base in a sort of crescent shape. I then blurred it.
https://s25.postimg.cc/qb9tcaev3/image.png

Then, making a new layer, I draw the base of the cloud. Use the off-white color I presented with the original color selection. (Or, you can use white. It's up to you, grey could work for a more rainy look, or even a yellowish color for snow.)
https://s25.postimg.cc/b2jvyiswf/image.png
Place the clouds in a way that you feel natural, or fitting for the type of day you want (Cloudy, partial, etc)

Then, simply invert the brush by clicking this little icon next to the brush~
https://s25.postimg.cc/5edl7mw9r/Invert.png
And turn your brush density to 50%, this will make the job of erasing SO MUCH easier, and less over done.
Don't erase the entire thing, only go up to the edge of the cloud.
https://s25.postimg.cc/s32s77t33/image.png

Then, do it with the rest~
https://s25.postimg.cc/lcmaxslcv/image.png

Now, I thought it was just a liiiitttle too clear, so, I went to Layer>Copy and it made it thicker
https://s25.postimg.cc/ojguhh38v/image.png

Notice how there DOES seem to be a few times were I managed to make it outside the cloud? That's okay! Look up at the sky on a cloudy day, and you'll see it's sometimes a little messy there too.
I also made it appear that two clouds weren't condensed. This makes it also look much better, but I didn't do it with all of them.

Partial clouds is all the steps BUT you don't stay within the cloud.
https://s25.postimg.cc/kodgegp3j/image.png

But, back to the complete clouds, I added lighting. I used the color displayed https://s25.postimg.cc/iwkhjnswv/image.png

Then, finish it off with maybe some grass/scenery, or leave it as is uwu~
https://s25.postimg.cc/m4oyx2hv3/image.png

And you're done~!
Let me know what you made if you try this, I'd love to see it!

Amazing!

What site do you use to color it?

Thank you

Pain Tool Sai

Got a laugh from that for some reason x3

But this is cool and detailed. Thank you for making this!