Mix and match furniture just like you would indoors. Matchy-matchy outdoor dining sets are no longer required; today there are many options for furniture that can stand up to the elements. Furthermore, a porch roof provides ample protection for most of the year, as long as golf-ball-size hail isn't coming in sideways.
If space is limited, treat one corner of the porch like a small breakfast nook. A small rounded table and two to four chairs can cozy up into a small space and leave room for settees, rockers and armchairs on the rest of the porch.
On a screened-in porch, place a round table in an outer corner. This maximizes the views for as many people at the table as possible.
Take cues from your formal dining room when it comes to hanging lighting. This onion lantern pendant has exterior style, but it's hung in an interior way — centered over the dining table.
Let your rustic flag fly. If some of the previous images are a little too formal for your ideal porch, by all means, go more primitive. This charmingly rustic porch and its coordinating twig furniture create a comfy picnic atmosphere where you can pretend you're roughing it — you know, like MBAs on a dude ranch.
Add an outdoor kitchen. A porch provides great cover for cooking al fresco, and you won't have to carry the serving plates very far.