From the blog of Rachel Poli:
Just like naming your characters, naming your world and the places inside it can be difficult. You should give it some thought, but you might be able to just write down whatever comes into your head first.
1. Have names your readers will remember
Everyone knows Hogwarts. We all know Mt. Doom. They’re not fancy names. Hogwarts is out of this world while the word “Doom” is simple and common. Names don’t have to be simple but they should be memorable.
2. Avoid names that can’t be pronounced easily
Short names are good, long names are fun, a mixture of the two is great. However, when it comes to any name, you should be able to pronounce it easily. Even if your readers have to stop to sound it out, they should be able to make some sort of sense of it.