I try to keep my classroom both businesslike and friendly. From the very beginning, I establish that we will do a lot of work and there is no wasted time, but we will also laugh and I will tell corny jokes. I tell silly jokes and smile a lot from the beginning to show that I am human and not scary. I also have students working, and working together, from the very beginning. I try to keep things light but busy. I think that classroom management breakdowns happen from the very beginning, and if you establish a pattern from the beginning you will avoid trouble later on. How you react to the small tests that students give you in the beginning sets the tone forever after.
In terms of teaching, I try to have a balance of time-to-work and time-to-connect. I want my kids to feel comfortable while they are with me, able to express themselves without fear of censorship, but also show respect for each other. I hope they can laugh, but not at someone else's expense. Learning is why we are there, but enjoying the time we have together is important because "we will pass this way but once." And as someone said earlier, I'm strict for the first marking period: it's not a party, but we find our comfort zone and move on from there.
In terms of the environment in my room, for years I have taken a lot of abuse from my peers for how I decorate. I have posters everywhere and things hanging on the walls. I collect bumper stickers and I put them on posters, along with quotes by writers, songwriters, etc.
My philosophy is that after 8 or 9 minutes, when the commercial interruptions break into the cartoons, kids lose interest. They have an internal clock. So I give them things to first make them comfortable. Second, I give them things to look at that will hopefully occupy their minds until they "come back." My kids have always talked about how much they loved my room when they were in class with me.
We spend A LOT of time together over course of the year, so I try to make them feel at home. We do the same for them all through elementary school, but start to slack off in middle school. Why do we stop? We should engage them as long as we can; it's what they know, and what makes them comfortable. And even if they start reading quotes from Mark Twain, James Taylor or The Matrix, they don't "stay away long..."
I would agree with the above posts in that children need to feel safe, not only physically but also emotionally. As someone else mentioned they need to feel safe in sharing their thoughts and ideas. I think it also depends on wht subject you are teaching and at what grade level.
A classroom should make students feel safe in the appropriate expression of their ideas, so appropriate has to be taught. It should also have a teacher who establishes boundaries and structure needed for the students. As clairwait has mentioned some classes cannot handle less rigid structure while others can.
I agree with the best environment being one in which the students feel "safe" and for me, this means emotional and physical safety. This is why I always start the year with very rigid boundaries (both physical and emotional). For example, there is a seating chart on day one. Students enter, find their assigned seat and sit. Most kids are intimidated by me at first and think that I'm very strict. My first priority is to learn everyone's names.
Once there has been an established sense of respect I lighten up. Every class varies on its ability to handle situations with maturity or not, and if I have a class that cannot handle deviating from rigid boundaries, I am okay with being the "mean" or "strict" teacher.
The physical environment of my classroom is a 26 year old portable with a leaky roof, no insulation and mold. There's not much to work with, which has made me concentrate on the educational environment so the physical one is less distracting.
I practice Socratic methods of teaching whenever possible. I use humor. I act. I want them to learn my subject matter, sure, but I also want them to like my subject matter, so that they will learn it on their own, for life.
The best environment, without question, is one in which the students feel safe. I believe the best way to create this is to treat students with respect. Clearly firmness must be established so they will also respect you, but if teachers treat students like they are nothing more than receptacles of knowledge, those students won't think they are cared for, so there is no reason to listen.
I often explain why the rules in my room are in place and ask for comment about them. I use questions like, "Do you think this is fair?" "Do you understand why this is important to me?" "What types of things are important to you?" "Are there any rules I have missed that might make this a more comfortable learning environment?"
My preference is to have a classroom that does not have rigid rules. I want to create an atmosphere in which students feel like they are able to say what they want without fear of saying something wrong and in which students do not feel like they have to constantly be worrying about rules. You must note, however, that I teach high school, mainly juniors and seniors and this would be much less appropriate in a classroom in middle school or below.
Because I teach history and other social studies classes, I want my students to feel like they can speak their minds. I think that this helps them want to engage with the material I am teaching. It is also necessary because some discussions require them to talk about personal beliefs and things like that. Because of this, I need to have a less formal atmosphere, one in which students can feel more like themselves than they might in a more structured atmosphere.
I teach at risk students and in an inclusion program so my methods are usually a little bit different to try to facilitate student involvement. Walking into our classroom you will find a warm, fun environment where everyone has a voice and is free/safe to voice their opinions and answers. We try to run our classroom as a democracy, I give the students choices on what order they want to do things and I explain my reasons for wanting to do things a certain way. In high school, this works really well because the students feel like they are in control (eliminating a lot of angry resistance) while getting the work done. We like to have fun in our classroom and proudly display our work on the walls outside of our room. I've been teaching for 3 years at my school now and actually had a waiting list for my upper level environmental system class. When students want to take an extra science they don't need, makes you feel like you did something right : )