Saying "porch" feels so retro, though, and saying "terrace" brings a bit more of a sophisticated vibe, like "antique" or "vintage". The thing with terraces is that they are supposed to feel warm and organic regardless of the time of year. It can be really easy to over-embellish in the process of trying to make this happen, and I have found that it is crucial to work with what you have. One way you can do this is by adding a faux brick wall to the side of the house that the terrace is up against. A faux brick wall is going to have a natural, comfortable presence, eliminating the unfriendliness of synthetic materials like siding, or chipping paint.
I think plants are just a must when it comes to a good terrace. Giant potted plants in the corners and along the sides will offer privacy and ambiance. I would absolutely suggest adding a pergola, and growing some creeping plants over the top of it to shield out the sun. If you don't want to use the plants as a shield because you don't want to keep the sun blocked out all the time, there are canvases you can purchase which will provide you with the option of stretching them over the pergola for shade or folding them back when you want sun.
Regardless of what you do with the top, there is no good reason not to incorporate curtains along the sides. Sometimes when you live in a more populated area you just want to have the feeling of being a little more isolated every now and then.
Of course all of this will be obsolete if you throw out a couple of folding chairs and an ash tray and call it a day. If you're going to create a terrace, even investing in the faux brick wall and a pergola and plants, then take it to the finish line by providing some amazing patio furniture. A gorgeous wood bench would provide a cozy seat for two and would hang nicely from a pergola.
When it's all said and done, don't forget about sound! Sight, touch and smell are easy to accommodate, but as soon as you sit down, you will notice how quiet it is, and stretching cords all over the place for speakers and radios will just get in the way (literally). Install some wireless speakers, or maybe even a small fountain. If you don't plan on going that big, maybe add some wind chimes.