You should know which style of a living room do you want, even if this was just an image that you imagine in your mind. Decide if you want the style to be classic , modern , or rustic. In this you can benefit from decorating sites, or furniture magazines. Your living room should reflect your individuality.
Furniture items needs to fit the space they are going to occupy. If you have a small living room you should use smaller items, as this will make the room narrow and cramped.