Articulating your beliefs
I highly recommend creating a list of basic working assumptions that define your beliefs about what school should be. Creating this list can serve the purpose of refining your own understanding of your job. It also serves as a powerful springboard for conversations with your students about what you will try to accomplish together.
Define your working assumptions in language that your students can understand. Your words should challenge them to grapple with those ideas and help them to see whether they share your beliefs about school. Coming to a consensus about these ideas is the starting point for building the classroom culture.
Your goal is to break through the unexamined beliefs underlying doing school and get your students to understand why they need to replace it with genuine learning. Breaking their well-established habits will be a long and difficult process. You want to kick-start that process in a powerful way right from the beginning.
An example
Here is a list of working assumptions I handed out to my students. I found this to be very useful in launching conversations with them about the nature of school, what they thought was working and what was not. Feel free to use my list as a springboard for your own. I would recommend reading it, then putting it away and writing down your own.
After getting students into small groups (four or five), I handed out this sheet and encouraged them to go through it one statement at a time. Their job was to decide which assumptions they agreed with, and which they disagreed with. I also asked them to decide on the most important assumption, the one with the most potential impact.
After giving them 15 or 20 minutes to talk it over, I would bring them back to a whole group discussion and have one group at a time say what they thought was important and why. This led to many discussions around the nature of school, how students are treated, whether they can be trusted, whether school is really about learning, and so forth. Above all, it allowed me to express my posture towards school and what I wanted to accomplish as a teacher. It also led to more clarity about the nature of the classroom culture I wanted to create.