So you have no windows in the living or dining room? First, develop a focal point if there are no windows, fireplace or special architectural features. Don't know your style, but you could put a gel burning fireplace and bookcases on the end of the living room like pic #1. Dining is naturally just next to the kitchen and that area could feature a banquette on the end wall of that space similar to pic #2. Since you rent, you can imitate this look with a free-standing electric or gel fireplace for the living room, flanked by a pair of bookcases. Hang the TV above the FP and float an apartment sized sofa out in front of it. Use a glass coffee table and two accent chairs that swivel and turn for watching TV. They should face each other over the coffee table making a "U" with the sofa in front of the FP. Put a sofa table behind the sofa. Use an arc floor lamp to arc above the coffee table and anchor all the seating area on a large rug. For the dining room get a banquette and a trestle or pedestal table plus a couple of chairs for the opposite side of the table from the banquette. Fill your walls with large colorful art pieces. "Mouse over" pix to enlarge them.