Two words: FIELD TRIPS!!!!!
One of the things *I* find most interesting, AND helpful, is to learn other things going on at the time we're learning about. What was happening in medicine, music, art, who was leading major areas of the world like Russia, England, ... etc. When you talk about George Washington, which states were formed that he would preside over? (Not WA state!) hehe
What movies and/or books were written during that time or about that time? For example, Little House on the Prairie stories as well as Gone With the Wind were happening during the Civil War period. Did they have electricity anywhere? Indoor plumbing? What music was "popular"? Did *everybody* wear hooped skirts or just those at city/county parties? Maybe that sounds like a bit much and all of it doesn't need to be included every time but I would definitely try to find some historical fiction choices for the students to read about the time period being studied.