Lace is a classic and elegant fabric that is always in fashion. Slim dresses are still around, however the full princess looking skirt is back. Bolder looks for fall, including treated fabric are everywhere. This means heavier looking fabric, creating again, the full looking dress. We are also seeing a lot of details on the back of the gown. Whether exposed with detailed stitching or beading, the back has become the new front.
As for your gown and headpiece/hair style, there are a lot of factors that determine the best styles, so they are quite personal. However, your wedding mood, location and season can affect your choices.
Wedding attendants can wear colors that reflect those of the season. It may be cooler in the evenings, so have the gowns made from a heavier fabric such as brocade or velvet or have a wrap.