My son is a sophomore at Godwin HS. Our experience has been very good so far. I highly recommend that high schoolers find some extra-curricular activities to join. It helps them find a way to fit in and feel like they belong. It also, in some ways, makes the school a little smaller, more manageable, less overwhelming. Whether it's sports, drama, dance team, community service, robotics, there are lots of options. Some of them meet everyday others once a month. Find something that works for your child and captures his/her interests.
On the opposite side of the coin, there are lots of opportunities out there which means choices need to be made if you and your child are going to survive high school.
Choose your child's courses carefully. Know what they can handle and do not push them too hard. Honors and AP classes are great if your child is prepared for them and will not be overwhelmed. But you can pick and choose. Who says all of your child's classes have to be advanced.
All teachers are different. High school is yet another chance for your child to learn to deal with different personalities and teaching styles. This is good and bad. Their grades may suffer a little in a class where their personality does not mesh with the teacher's. But in the long term, if they stick with it, they will learn how to get along with someone who thinks and works differently than they do. This is a great life skill to have.