Finding authentic or authentic-looking fabrics, ribbons, etc. for historical costumes is quite the challenge especially if you only have big-box stores like JoAnn's to go to. Doing adequate research and even keeping a fabric journal can help. Some things you will need to find online, but you can make do with a trip to JoAnn's or Hancock's if you know what to look for and where to look for it. I found this article from HistoricalSewing.com to be a great help, especially for beginners:
You'll also see on the right side of her page a place to sign up using your e-mail address to receive a free copy of "7 Strategies for Creating Realistic Historical Clothing from Chain Fabric Stores". It comes as a .pdf file and I found it quite helpful, even with some experience under my belt!