The main subjects usually covered in "Introduction to Jewish Studies" courses are Jewish history, beliefs, and practices. That is a huge amount and each instructor develops her or his own style. I am a historian so I begin with history, which I think is necessary to understand the development of beliefs and practices. History also encompasses topics in which some students have particular interest: the Bible; the relationship of Judaism to Christianity; the Holocaust; the State of Israel; and contemporary Jewry.
There is usually a core textbook to which other readings—primary and secondary— are attached. After trying a number of these I now use Nicholas de Lange's excellent Introduction to Judaism. It is readable, it covers the topics I want to discuss, and it avoids most of the denominational slant that colors many introductory works. Instructors often use Barry Holtz's standard Back to the Sources. I have not found a text reader that really works for me so I cobble sources together from various places. Many of them are now available free on the internet.
One problem I have found teaching the introduction is the varying levels of student knowledge, from the day-school slackers to people who never met a Jew before arriving at Ohio State. A few years ago I was doing my standard "all of Jewish history in forty minutes" schtick (with jokes, of course). I had just hit minute four—Abraham, Isaac, and Jacob—and I thought I was doing great, when a student in the second row put up her hand. "I have no idea what you are talking about," she said. "I don't know anything about these people and I have no idea what you're saying." She was applauded. I had to rethink the assumptions I could make about student knowledge. This is tricky and I have no clear solution.