Please permit me to endorse the posts that have gone before mine and stated some of the right answers for reducing time spent on classroom management better than I can: meaningful, relevant, challenging learning delivered to the student in the student's learning style. Postings by Jim Nourse and by Judy Horner are two of the best for articulating these strategies.

I think "all of the above" a better , truer choice. There is, however, no substitute for experience: the longer one teaches, the easier the managment gets.

So that begs the questions "How do we attract good new teachers?" and "How do we keep teachers in the profession long enough to get good at it?" Smaller class sizes are probably the best single thing we could do to keep nwebies from burning out, but better training and administrative backup also helps.

In the larger picture, I think society has to come to a point where we actually value things like education, attention, nutrition, hard work, strong parental support, and a few of the other things missing from too many kids' lives.

My experience as a high school teacher and principal is that most of the misbehavior that requires excessive classroom management results from disengaged students. When students are known well by the adults in their lives, including their teachers, when they feel that their learning is relevant to their lives, when they feel that they are being challenged to solve real-world problems and are held to high standards while being supported to succeed - that's when students will cease acting out. To continue a system of educating high school students based on the premise that they all learn in relatively similar ways at the same time and at the same rate, flies in the face of not only current research, but our collective instinct as parents and teachers. One size does not fit all, and we must embrace the messiness and multiple avenues for learning that this implies.

Disengaged students prevent learning from taking place. Students who are referred to administrators three times should be removed from the traditional setting for an entire semester. Students who are willing to learn should not have to put up with those who have no desire to be educated. Make the students accountable. Stop blaming teachers, class size, etc.

No matter what 'type' of students you have (gifted, special needs, high achievers or low), too many students in any classroom spells disaster!
My classes are 34 students each, on the high school level. These classes are mixed in ability levels, so you have gifted kids with superior skills next to kids who can barely read or write, or speak English. In classes like this, even students with the best 'manners' fall victim to the old "teacher is busy with the neediest kids and never pays attention to me" mindset. Classroom management becomes crowd control.
We are trying to hold students accountable for their work and behavior, but how can we assess the work of 34 students in 45 minutes, and still teach a lesson, take attendance, deal with interruptions and model good citizenship? If classes had 12-15 students each, imagine how much more work we could expect each day! Imagine how quickly we could return essays--and ask for new ones! Imagine how easy it would be to spot behavior problems, how much harder it would be for slackers to hide in the crowd!
Ok--enough imagining. I have essays to grade--34 to a set!

It never fails that when classroom management is brought up, we are asked if we have enough training and preparation. We just have a relatively low number of children who come to school unprepared for life with other people. They have been neglected by their families, no friends of families have stepped in to help, there has been no faith based connections or support for the family, there has been very little positive governmental support for the family, and you ask us if we are prepared for classroom management. The answer is yes we are prepared to manage our classrooms. Not only that we know that we have police liason support even if we do not have district or administrative support. We also know that our classes are overcrowded. You know if you have empty rooms we have to close the school and keep at the one-size fits all model. We warehouse children to the point where I, for one, am convinced that there really is no educational conceptualizations from our leaders. there is a large baby sitting budget, and a fierce hatred of teacher unions. It seems to me that there is some spite your face problems with education policy.

I taught in a large urban high school with large classes (32-35) and a small rural middle school with reasonable classes (16-20). It may sound trite but the same method worked with both of them: I was firm, fair, and consistent in terms of discipline. The expectation from the first day was that we had to work together if the class as a whole was going to be successful. Rather than spending the first day going over the rules (the same ones that had been exposed to in every class for every year they had been in school), we started working on content on the first day and I pointed out and modeled the rules in action. The message was the we had serious work to do and didn't have time to worry about discipline.

I also took a lot of time teaching classroom procedures to help with classroom flow, particularly in the large classes including how things got handed in, how students found out what they missed (absenteeism was a problem in the urban school), etc. Technology helped because in 1989 I adopted a grade book program that spit out a list of missing work that I could post every day if I needed to.

I still had the occasional serious discipline problem, and then I would enlist the aid of administrators and counselors to help provide a place for the student to go when he or she simply couldn't be in class. I tried always to avoid confrontations where there was the risk that I would lose my temper. No one wins when teachers argue with students.

It is a combination of things. From engaging the students, to the mix of the students, to the organization and presentations skills of the teacher, to the discipline policies of the school, to the expectations of each student's parents of that child. There is no one simple answer for everything.

Getting disruptive students out of the classroom would, in my opinion, do the most to affect good classroom management. Few schools have a mechanism to get disruptive students out of the classroom so that others may learn. Few schools even punish disruptive students to the extent that they won't do it again. Fewer schools even know how to keep some kids from making it impossible for others to learn.

Young children LEARN by being given good examples and plenty of time to practice the skills that they have observed.
I have found that the more time you take in the beginning of the year to establish joint ownership in the classroom between the teacher and the students, the better the climate and the behavior in the classroom.

Especially for children under the age of 8 years, they need to be involved in setting the rules of the room, knowing the consequences of both positive and negative behavior; learning to verbalize their feelings - instead of being physical; learning to negotiate and developing respect for their peers.
It takes time and is often left behind. It is the kind of learning that has a long term result and on which we should spend much more time.