I'll take a bible book (currently Isaiah) and read it through, one chapter at a time, using my NIV reference bible. After each chapter, I read all the footnote comments. I then consult online commentaries such as Coffman's (available at StudyLight.org) if I have further need of enlightenment or simply to get another viewpoint.
While I do this on my own, I have gone to a neighbor's home recently where a group meets for Bible discussion. Right now they're covering John Piper's book What Jesus Demands From The World and they read some Bible verses that the book includes or comments on. The jury is out for me as to whether going to this study is worth my time, though it's very casual and I like the idea of just popping over to my neighbor's house and not having to dress up to attend a simple bible study meeting.