I've mentioned in passing once before that one of my favorite new silhouettes to wear is a cardigan over a dress with a belt. The open cardigan creates a vertical line down the front of the dress that fools the eye and makes you look thinner, plus you look semi dressed up but not like you tried really hard. The look works with boots and flats (or heels, I guess) and you can add tights to make it winter-friendly.
Here are some outfits that you could put together now (pretty much everything shown is available now):
At Work: Banana Republic dress, Old Navy Cardigan, Nine West shoes
Church or Bridal Shower: J.Crew dress and cardigan, Nine West shoes, Belt by Peacocks (UK)