An old screen door became a keeper and I loved using it to add architectural interest and break up the space between open concept dining room and kitchen. (followtheyellowbrickhome.com)
Using furniture or rugs will help to visually break up a space into zones — crucial for making a large room feel comfortable instead of overwhelming. (lindsayhillinteriors.com)
I also like things that are a bit asymmetrical, something you accomplished by breaking up that space. (sewchet.com)