By the way, I hope you're using a licensed real estate professional to help you with the sale of your home. If not, I'd be happy to help you......
I think a moderate amount of furniture is good. It helps people get a feel for how big (or small) the room is.
For example, in the living room I'd put a couch (or loveseat), maybe a chair, a coffee table and maybe a lamp and some accessories. I wouldn't fill the space with more furniture like end tables or sofa tables, or multiple couches.
For a small bedroom you wouldn't want to put in a king size bed, plus side tables, plus dressers! I'd put in a queen bed and a nightstand and that's it.