Reflection #1: Scope
One of the foremost questions we must deal with has to do with what is really important. What irony! It’s too important a question to be thought about before one has any real awareness of the educational process, but one can't really teach effectively until one comes to grips with the question. (I hasten to assure you that there will be no definitive answers. There will only be increasingly imponderable questions...but then, oh, well.)
It seems to me that, for starters, as a brand new teacher or as a student teacher you won't be in much of a position to actually determine the content of your courses. You will teach, at first, from course content determined by others...by teachers past and present who have chosen the text you will use. (After all, the astronomical price of textbooks won't let us change our minds all that often in our teaching careers.)
Nevertheless, the content of the course will yield to the demands of the people who employ you, the parents of the students to whom you are in loco parentis. Like it or not, those parents have a number of things to say about what their children should be taught. You may feel yourself to be far more knowledgeable and worldly than your clientele, but the fact is, you can only lead, persuade, and beguile; you cannot always dictate.
In addition, for good measure, you can add to that combination, the wise thinking of various state agencies, the contributors, editors, and publishers of the textbooks, the ideas advanced by the elders of the profession and anybody else who cares to sound off! Fat chance of your determining anything for awhile! The best you can do that first or second year is to get acquainted with the content of your courses, always asking the question, “What is important enough to make this worth teaching to these precious kids?”
Conclusion: Bottom line, of course, is that the material you teach to students ought to be, in your mind, demonstrably meaningful enough that kids ought to learn it. If you can't figure it out on your own, then, for heaven's sake, ask somebody! Don't just automatically assume that the material is either important or unimportant because of your personal opinion. Maybe you'll be stuck with it for awhile; maybe you'll change your view with guidance from your mentors, but just maybe, your initial reaction will have been correct, and the content didn't deserve to be there, and nobody had noticed. At any rate, the process of asking the questions and determining your answers will make your teaching meaningful. After all, if, after due consideration, it truly isn't meaningful for you, maybe there's a failure to communicate somewhere, and it must be remedied before you can effectively teach those kids.