Every writer has to create a world for their books, even if their books are based in a real time and place. You still have to create that in the reader's mind out of nothing. You may have a reader who doesn't know what living on he beach is like, and that means you have to be the one to tell them. No matter what sort of setting you're creating, do yourself a huge favor. Base it on an actual place that you can find on a map.
Pick a Real Place for Your Setting, Or Else
No matter where your book is taking place, you must give your readers some frame of reference. If you can make me understand that snow is frozen water and it's capable of falling from the sky in soft, icy little pieces, you've done your job as a writer. But you can never make me understand what glub is when it gets on your hands unless you can compare it something I do understand. If you tell me that glub has a slimy texture, I'll get that. You have to do the same sort of thing with your setting. You've got to ground it in something I understand.
You've got to pick a real place, somewhere, and use this as your foundation.