Yes, yes, I know I didn't post last week, and this will be it ere I head off to DC with hope in my heart and a lump in my throat, but there are just so many hours in the day, so here is my "off the cuff" offering---which happens to contain more than a smidgen of sense (imagine that!)
Children's Books. Yep. That's it. When I start any research project, the first thing I look for is a book written for children centered on the era or subject matter. Why? These books are full of general information that often provides stepping stones to the more nitty-gritty stuff that makes our work shine. AND they often contain snippets that our adult minds might overlook.
One of my favorites is a pop-up book, Castles---Medieval Days and Knights by Kyle Olmon. Love it. Three dimensional overview. (The little pull-out tabs that make the blacksmith work and the spinning wheel go are fun too!) I love the pop-up of the banquet hall (shown above---poorly, I admit. I'm a writer, not a photographer) with the knight kneeling to be dubbed because, when writing a scene within such a hall, I can set it up so everyone stays seated where they belong. (There was a protocol to such things!)
DK books (http://www.dk.com/) has an Eyewitness series with available workbooks. Some come with DVDs of Clip Art or posters and other visual aids. The books are informative and well-written and hold a surprising wealth of information
I won't bore you with the extent of my "Children's Book Library" but will encourage you to build one of your own. These books don't go into the extensive detail of more intensive research, but they're priceless for general information and direction. I have one that is specifically geared to a child's life in a medieval village that has proven it's worth time and time again as I write beyond the castle walls.
So set your inner child free and go play in the kids section of your favorite bookstore, whether virtual or physical. It's a treasure trove waiting to be found.