Choose furniture that fits. If the corner is fairly small, pick two overstuffed chairs to make an intimate area to sit in. If the space is a little larger, start with a loveseat and add as many chairs as needed, or make the seating area special for one with just a chaise lounge. A window seat can also be transformed into a seating area.
Pick comfortable elements to make the seating area a cozy place. Fill the couch, chaise or chairs with soft pillows. Place ottomans next to chairs for guests to put their feet up. Toss a fuzzy blanket over the couch for chilly evenings or an afternoon nap.
Let some light in. If your seating corner happens to be near a window, make sure it's easy to let natural light in. If that isn't possible, place a lamp or two in the space so it's not a dark, dank corner with no light. This also creates an intimate feel for conversation.
Add a table. A seating area, no matter how small, needs a small end table or coffee table to rest a snack or drink on. Pile a few books or magazines on the table, or add a personal touch such as a favorite knicknack or scented candle.
Make sure the furniture pieces face each other to create a more private feel to the seating area. Block off the area if desired with a large piece of furniture such as a shelf, or try a folding screen to make it more secluded.