In the old days, you had to pass chemistry and Algebra 2 before signing up for physics. Those prerequisites considerably narrowed the potential population of physics students. And the big secret? It turns out you can teach a perfectly good physics class to students who have not passed chemistry or Algebra 2. For a first-year physics course, there's no reason for either of those prerequisites. Let them go!
Will you end up with some "less-qualified" students in your classes? Yes. But accept the challenge and work your craft. You are fortunate enough to teach physics, so teach physics! (And rejoice!)
I don't encourage Honors Physics. I like a "big tent" in my Physics 1 course. Heterogeniety rules! I strongly recommend heterogeneous lab groups. Email me for details on how to make that happen.
Make it possible for all students to succeed. Not all students will succeed, mind you. You cannot have complete control over that. Without the barricades in place, you'll have students who don't intend to be scientists or engineers. And that's OK. Working your craft as a physics teacher means you'll have to guide those literature, arts, and athletic types to success in your class. They won't all follow, but success has to be accessable.
A wise vice principal once told me, "Not all baby sea turtles make it to the ocean." But let students choose their path in your course. Lay out the options. Make them "doable," and let students decide with their actions. You might worry this will water down the rigor of your course. I can say that I get some really bright students at my school and if even the smartest among them was ever bored in my first-year class or felt unchallenged, they never told me.
What am I suggesting, specifically?
Don't put all the weight of the grade on test and/or exam scores. Allow for the fact that some of the ideas of physics require time to settle in. Let students review tests after the fact. (I use a technique called "Test Correction Journal." Topic for another post some day.) Then give them more questions of "old" material on future tests. In EdSpeak, that's called "spiraling." Whatever it's called, it allows time for material to settle, and engenders the idea that "old" material is still important. As the semester progresses, unit tests look more and more like mini-final exams. And that's OK.
Don't grade homework for correctness. Credit for homework is tricky. Students want it and teachers don't want to give it. My analogy is to ask student athletes about practice. "Before the match on game day," I ask, "how many points do they put on the scoreboard in recognition of the practice you did all week?" There are clever ways to encourage the completion of homework. I use a technique called "The System" which is a general method to encourage good academic behaviors and discourage the bad.
Don't forget to have some fun from time to time. Throw eggs. Do groovy demos. Show Roadrunner cartoons. Laugh. You're teaching the grooviest subject on campus; there's gotta be some fun in there somewhere.
The biggest challenge for any physics teacher is simply to remember how hard the material was the first time. A tall order, especially for those of us who have had significant coursework and years of experience. Doubly challenging if physics came easy to you. (Happily, I was never "cursed" in that way.)
If you've got Algebra 2 and/or chemistry barriers in front of your physics course, you're keeping a lot of good students out of your course. And denying them an excellent high school physics experience. Don't do it!