I think (and hope) that all those who prepare to become teachers dream to become great teachers!
Obviously that depends on how much, and how well the teacher knows her/his content, and what skills for teaching s/he has.
Creating a warm environment is just as important as planning well the lesson; but these will be done well only if the teacher knows his/her students.
I think my students already know what I will say (and roll their eyes as well :-)), when I stress (and cannot stress enough) that they will have to build a classroom community, to know each individual, and remember that even if they teach a class they have individuals. Each student has a certain level of cognition, who have a physical and behavioral individuality (which can change from one day to the other), and they are emotional beings.
In our teacher preparation students take the Methods course where they learn how to teach in their content area. For that reason I do not stress in this course lesson planning. However I mentioned that feedback is very important. A good feedback looks like a sandwich: what was not as good; what was good; and how to make the not so good to be good. We all agreed that grades are useful since they tell us the level where our performance is, however, we all hate to only receive a paper back with a grade and no feedback at all.
And if we talk about feedback we must talk also about teacher expectations. I had students who needed extra encouragement, support, monitoring, and sometime a little push. I believe that with hard work my students can succeed. The time spent to learn is dependent on how much time each of my students has allocated to study, and how much of that allocated time is actually on task :-)
Rosenthal (1968) draw our attention to the importance of teacher expectations in the classroom with his famous Pygmalion in the Classroom.
Is truly sad to hear any teacher say "that student will never be good of anything."
When this topic comes in discussion all of us are aware that we have individuals with different intelligence, potential, skills, and motivation. And even with the current Race to the Top, NCLB, no teacher will bring every student to perfect score. And no one even asks that. What is asked is to teach the students to reach their best potential! We must have high expectations and realistic ones in the same time.
To reach that potential for every student we must teach for deep understanding, critical thinking, and use authentic instruction/assessment which will give the skills necessary to apply in real life. We should keep in mind the classroom as a community, formed by individuals with different skills, intelligences, and motivation. Differentiated instruction gains more ground and preservice teachers are prepared to modify the elements of instruction to meet students' needs: modify the content; differentiate the process; differentiate the products that result from learning; modify the learning environment; and modify the classroom climate.
Since each student in our classes is an individual, we expect that they will have different motivation to learn, and might think differently about their self-efficacy, self-esteem, and obviously make different attributions of their success and failure (Weiner, 1980). They value or not what they learn, and expect, or not to succeed.
All these differences and individual variables must be taken into account when we design a lesson and when we teach in the classroom. Always expecting that students will be able to perform, structuring activities so each individual can benefit at oen point or other, targeting students' interests and motivations, and helping them take responsibility and value their learning.