This fashion plate appeared in the French magazine La mode in 1838 - founded in 1829 by Henri de Giardin (and not to be confused with all the other magazines named "La mode this" or "that". The setting is outside - but it is in this case a thin line between what would be called a day dress and what to label as a walking dress. It is also worth remembering that even though an ideal woman would have had both (and several of them too), in reality this seldom happened. A dress had to function as both, with another for Sunday church services. It is also worth noting this did not just apply to really poor people, clothes were expensive and rarely mass-produced at this time which kept prices high.
These dresses are very typical of the 1830's - the early Victorian silhouette with a really thin waist (of course achieved by a corset), a wide skirt and equally wide sleeves (though later on in the century they would get even wider), giving a plump hour-glass-figure to the wearer. This was even more evident in fashion plates than in reality with the shoulders being drawn as extremely slanting making the women look like fragile dolls.
The fabric of these dresses were in all probability cotton, which was easy to use and not too expensive - dyed in light, blue colours. The dresses in the 1830's were generally of some light colour, sometimes with a print - then often stripes or flowers. And then there was lace. Lace was really popular, but a luxury just for those who really had some money.
The accessories are the usual for a portrait like this: bonnets (because every lady had to have something to put on their head if they ventured outside - and bonnets were much more common than hats at this time), gloves and a parasol. You can also note some really pointy shoes, which seems to work the same way those impossibly thin waists did in these fashion prints - they were very popular to draw, but in reality it never did look that extreme.