As you enter the classroom, there is a word in your vocabulary that I recommend you drop rather quickly... the word "should". This word can become a roadblock between you and improving student performance - the entire point of your job. A lot of things "should" be a certain way, but are not. These can include student backgrounds, histories, and family situations, in addition school funding, administrative, and executive changes that are outside your control. As a teacher, you must keep in mind the realm for which you are responsible. You have intimate access to a student's growth and improvement, and you must not lose sight of what you can control for what you cannot.
With that in mind, it is highly likely, that the students you will deal with "look" far different than you did in school. That is, many to most may come from broken homes, poverty, and abuse - in addition to experiencing a distinct lack of success in school.
* What can you do to relate with and increase the performance of students whose childhood and school experiences are likely quite different than yours? (keep in mind how USELESS the word "should" is in this situation)