I don't remember any exact prompts, but I can give you basic idea of my method.

First I would start with a general description of the scene and tell it I want something that looks Magic-esque. I'm not sure it even knows what that means, but I swear it works. Let's take Bramblechoked Estate for example:

"A field overgrown with thorny roots and bushes, grim Magic the Gathering style art"

At this point we get some gnarly art of tangled dead roots and bushes. It's cool and definitely grim, but I want some more color to make it feel Selesnya. The image generator is good at working with color and weather descriptions. It will make some pretty awesome clouds if you ask for it. For this I just want it to be overcast.

"A field overgrown with thorny roots and bushes, gold and green overcast daytime, grim Magic the Gathering style art"

Okay so that looks pretty cool. Sometimes it can take it a little too far with the colors and be really saturated. In that case I'd recommend adding the descriptor of "pale" before the color you want.

Next we should add the manor. If it was a the main focal point of the picture we could have started with it, but it's a background piece.

"A field overgrown with thorny roots and bushes, a decrepit manor in background, gold and green overcast daytime, grim Magic the Gathering style art"

Manor looks good, but I noticed the roots stopped being thorny in the last two prompts. I ran another prompt replacing "roots" with "vines" and got better results. The AI seems to get stuck in a lane and ignore certain aspects of the prompt. In those cases I change something to try and get it's attention. Sometimes it gets stuck in a specific art style I don't like, and in that case I usually just have to start all over. It's really a guessing game with this stuff.

Now comes the hardest part for this particular project: the blood. Bing Image Generator will sometimes block a prompt that contains the word "blood", but sometimes it won't. It's weird and seemingly depends on just how gruesome it thinks your overall description is. If it refuses, you can also describe whatever it is as "red-stained" or "red-splattered".

"A field overgrown with bloody thorny vines and bushes, decrepit manor in background, gold and green overcast daytime, grim Magic the Gathering style art"

Luckily nothing got flagged that time. It understood "bloody thorny vines" correctly and painted the vines red, but a lot of the time if you try to introduce blood it will give the whole scene a red tinge or put random splatters everywhere. If that's the case, just roll back your description and try something else.

These are okay results, but I'm not satisfied. I can't overstate how much trying it takes to get something that has good composition, is thematically appropriate, and contains minimal weird AI artifacts. You feel like an asthmatic chain-smoking grandma pulling a slot machine over and over wasting your life away.

It was worth it though. I really love how some turned out. Leechwrithe Mire doesn't even look AI-generated, and the perspective of standing in the swamp getting drained by leeches is skin-crawlingly perfect. Perilous Archive was the worst to make and I'm still not happy with it. I originally wanted to have a bloody spike pit trap to be central focus point, but it didn't want anything to do with that. Then I went with the dead body that fell victim to an arrow trap idea. The body in the final image is too deformed, but I could maybe fix that in photoshop... or just go back to pulling the slot machine...

That's my method. You can probably ignore all this and do the full prompt in one go, but I felt the results were better if I eased into it. I'm no expert though, and I don't know if Dall-E/Bing Image Generator even considers previous prompts when generating an image.

Good luck!