My first world map

[Tear]

Would you consider joining the two large areas in the middle?

I thought about it, but I think I'll keep them separated.

Is this based on a fractal world, or your own work, if you don't mind my asking? Because if it's the latter, I'd love a tutorial on your process.

It's all Photoshop. Here is a quick run-through:
I started with a rendered cloud layer in a high resolution (because the vanilla cloud filter does pretty large clouds) and put a threshold adjustment layer on top. Then I filled the areas where I didn't want any land to show up with black in the cloud layer using feathered selections. You could also use a soft black brush, I guess. Next I connected land areas using a big low-opacity (like 10% or so) soft white brush. I used the same brush to paint some islands in, just make sure you don't paint on the area you filled with black before. Sometimes it takes several pen strokes on the same spot to make the shapes come up where you want them.
Once all the basic shapes were done, I flattened the image and reduced the image size to half the height and width. The pixelated shape outlines get smoothed that way.
I used the result as a layer mask and applied some last touches to the land shapes there.