Love these sort of things.
This look great :3

Glad you do!
And thanks

very cool thumbnails :)

Thank you :)

Moar! Please.

Yesss xD
Just gotta make sure not to get annoying with spamming them xD

Man these just keep getting better and better! Nice job!

Thank you!

I have questions!!!
Do you grab a palette from an image? If not, how do you pick the colors?
How much do you use references?
Is it all on one layer?
What brushes/program do you use?
Do you have the idea in your head already or do you just doodle and go with it?

I start off with the canvas divided into the 6 spaces and fill them all with a single base colour, like a light green, brown or something the like. Depending on what I colour I choose I get a loose idea of what I wanna draw.
I actually didn't use any references at all for these but I probably should. Best thing would be to choose what you want to draw and then look up pictures of the area, to know which kind of trees and other vegetation grow there. Plants look different in a savannah than in a green mountain.

First of all, I uploaded an example for you here so its not as confusing :)
I use multiple layers.
1 - The base colour
2 - is clipped onto that so I don't draw outside of it and holds the loose idea of the environment. Sky, water, mountains
3 - is a multiply layer that darkens the image around the bottom edges (I usually use a dark blue or purple for this, but any colour is fine)
4 - is an overlay layer that brightens the image in the middle (for this one I like using a light yellow, blue or green depending on the effect I want)
5 - is detailing, this is where I put trees and rocks in the image, define the differences in the mountains etc. If I do any changes to the foreground to experiment I put them on a new layer so I can change those easily. I also use a new layer for creatures I put in the picture if I choose to do so.
6 - is the layer for environmental fog. Basically what I do is take the sky colour and draw a big blob in the middle with a soft brush to bring everything together a bit.
7 - then I do a colour adjustment layer or gradiation curves to change the colours and values if it didn’t turn out the way I wanted it to.

The program I use for these is photoshop, but you can do it in any program really.
And the brush I use is the same throughout one landscape. You can pick any brush you want, just stick with it until detailing phase. I used a hard square brush for these.

And as for the idea, its different for every landscape. The volcano was something I wanted to try out and the sky castle was requested by a rl friend of mine who watched me draw, but the others were just randomly created. I always start with the sky because that way you already make mountains/a nice skyline.

I hope that answered everything :)
I might actually upload a little walkthrough when I get the time to do so.
This is the video that showed me how to do it, he also has way more practise than me. If you have time you should watch it :)

Ahhh thank you so much for taking the time to give me all that info!!
I really appreciate it <3
I'm definitely going to try and do some of these from your advice, would you like to see how they turn out?

My pleasure :)

Of course! I'd love to see!