Here are some guidelines though
Tips & Tricks
Detail - Whenever building a map, detail is always important. | Refrain from making flat walls and straight roofs, spice it up a bit!
World Edit - Using world edit is going to make everything 10x easier. | Use //cyl to create the islands and //hcyl to create rings. | You can also use it to randomize the floor / terrain.
Use Color - Try to not make a map that is all stone and cobble, use some other blocks to make it look nicer, like
clay the base BrokenLens theme block.
Be Professional - When submitting your map, if everything is organized and you use the format, it's going to be appealing to the eye.
Interesting Gameplay - Try to make the game fun to play, avoid copying other maps and add a twist on your map.
Source:
https://brokenlens.xyz/forums/threads/how-to-submit-a-map.8/