Over the years, I have learned what questions I should ask that help me get a better handle on my students. But, I don't ask these questions until about four or five days in. [We do math right away, of course!]
Once I have all of the papers collected, I read them and then I put them in a three ring binder organized by class period. Often this first read through means nothing to me -- unless there is a red flag of a parent death or a particularly fascinating pastime like bull riding. When I have trouble with a student (not necessarily behavioral -- it could be just a puzzlement), and talking to the student one-on-one hasn't helped, I go straight to the binder. After I read through the questionnaire, I often have a plan. "First I'll call the parent, then I'll get in touch with the band director." OR "That kid is so-and-so's nephew? I will call the mom but I will mention that I work with the aunt."
I teach in a rural county school district that is near a major research university, so these are the questions I have come up with to help me better understand my students. You will have to tailor it to your school and to your students. But, this questionnaire is a start!