I found this site on Pinterest the other day and instantly thought about my brother and sister-in-law! By the end of the summer they will be moving into their very first house! And of course I am living vicariously through them. Occasionally I send them things when I come across something fun. The Make Room by Urban Barn is now on this list! The Make Room is an interactive program that allows you to arrange a floor plan by dragging and dropping furniture wherever you choose. Of course you will be dragging and dropping Urban Barn's furniture... but you could easily mentally substitute your own furniture in the mix by finding a piece of equivalent size.
There is always the tried and true way that my mother lays out a room. She takes graph paper and draws out the room on the sheet complete with window and door placement. Then on a separate sheet she cuts out tiny pieces of her specific furniture (all to mini scale). Labels each piece "sofa", "sideboard" etc and then puts tiny pieces of tape on their underside and moves them around in the "room" until she reaches a desired layout. It's really fun to watch her do this!