I taught high school physics for seven years before heading to PhD school, and the most important method for improving my own teaching was to observe as many other teachers as possible. In both my teacher education masters program and at the high school where I taught, it was mandatory for new teachers to observe other teachers multiple times per week. In fact, new teachers were given class observation duties that replaced other duties (e.g., cafeteria or study-hall duty) because it was deemed so important.
I found great value in observing all teachers, from the terrible (I once watched as a teacher ignored all raised hands and simply lectured in monotone for the entire class--the students looked like they wanted to jump out the window because they were so bored) to the outstanding, and everything in between. Obviously, you'll incorporate certain teaching methods into your own teaching based on your own style, but the more you observe, the more you'll see different variations and methods.
By the way, if you do want to figure out who the best teachers are at your school, you just simply have to ask the students. It isn't a secret, and the students see so many teachers every year that they will gladly tell you who is the best (and worst).
Finally, if you do want to visit other teachers' classes, it is probably best to ask ahead of time. While I wouldn't say it is rude to show up and ask to observe, it is courteous to do so ahead of time in person.