New writers, and I admit I struggle with this myself, don’t always recognise how much is enough, when it comes to back story and character description.
I have adopted the attitude that a little is enough. I can always add information at key moments, or introduce information through dialogue.
When I started my first novel, I knew I had way too much information. So I opted to use sparse character description knowing, in a series, I could introduce more in following books, without repeating myself.
With background location, I also try to use sparse description. I will carry a theme through the book, such as the heat or the sun, but the exterior “shots” I like to leave to my readers’ imagination. When writing about ancient Egypt, I think most people have preconceived notions about what it looked like.
In describing a room, I again try to just add enough information for the reader, without losing their interest. I cannot read a novel where a person or place is described in excruciating detail; I lose interest, I want to formulate a picture in my head, and it may not be the same as the author’s. That is part of the fun of reading a book.
Always leave something to the readers’ imagination. A few key elements, a well-placed description or facial expression, can add more depth to a story than twenty pages of well-written detail. It can be demoralising to an author, during the first, second, third, or fourth edit, when whole pages need to be cut, especially the ones you felt were the best you had written. Start small and add to the flavour of the work, piece by piece, rather than page after page.