Choose your fabric wisely since people may want to put up their feet (and shoes). Outdoor fabrics can be smart; steer clear of linen and fabrics with high amounts of rayon or viscose. Take a swatch home and test it out with dirt red wine or whatever you think your coffee table will encounter to make sure your fabric choice can handle it all. Keep an upholstered ottoman 18 inches from a sofa or chair so you can easily put up your feet and make sure the height is consistent with the surrounding seats.
When you have two sofas or any larger seating arrangement a big coffee table might seem like the obvious solution. But also consider a pair of matching coffee tables. They will keep the focus off one large piece of furniture and let your eye move around the room more easily. One classic coffee table size is 48 by 24 inches so you can plan on that when thinking about your furniture arrangement. A large coffee table is often double that: 48 inches square.