One of the problems of starting out as a writer is similar to one of the problems of starting out as a driver: you over compensate. If a new driver realises they're veering too much over to the left they yank the steering wheel round to the right, then have to yank it back again to the left.
Sometimes, if you point out something to a new writer, they behave in a similar fashion. Tell them they could do with a little more detail about the location and they immediately assume you mean pages of description. But you can actually create a picture about a place from very little description.
John entered the room.
Well, there's not much there to go on. Try this:
John entered the hall.
There's a bit more information, but the picture it creates is hazy.
John entered the Great Hall.
One extra word and the capitalisation might be enough for you but...
John entered the medieval Great Hall.
...you might need some confirmation.
John stared up at the massive medieval hammer beams supporting the ceiling as he entered the Great Hall.
This conveys far more information and becomes easier for us to imagine the room that John has entered and a little bit about John's attitude, especially if we add...
John stared up at the massive medieval hammer beams supporting the ceiling as he entered the Great Hall. "Wow!"
Okay, it's more words than we started with, but it's still under 20. So you don't need to add that much description to enable the reader to create a picture in their heads of your story world.
Anyone in St Ives for the September Festival? I'm giving a talk on Friday 23rd September at 11.00 am in St Ives Library. Go to the website for more info.