If you have lived in the same place for a very long time, you already know where your child is going to go to school until graduation. Unless you are willing to move, you don't have much choice in the way of what high schools you want them to attend. Your choices are usually the public and private options in your community. However, if you are planning to move, but you are not sure where you are going to end up yet, you can look into all of the schools in the general area to decide which you think is the best. There are many things to look for in a school and many questions to ask.
High schools are not all the same. Some are large, some are small, and some are going to disappear. If you had a bad experience in school, you may be looking for a high school that is the opposite of what you experienced, but you can never judge any school by the size. Smaller schools have more close knit classes, but that can be a problem. However, some children get lost in larger high schools and their educations suffers because of it. A middle sized school may be the best all around bet.
High schools can only work with what they have. There are many districts that have had to cut back on many programs that were standard when you went to school. Big changes have happened in some high schools in the last five years. If you have been out of high school for quite a while, the changes are even bigger. When you are choosing among various communities, request information about the the school budget and changes that have been made. This information alone can help you cross some bad high schools off the list right off the bat.
Take a good look at the sports programs at each of the high schools you are considering. A good program has plenty of options, but you also want a school that is not all about the sports. It is great for kids to play end enjoy sports for many reasons, but some high schools focus on sports too much, leaving education in second place. Even worse, those students that are not into sports may suffer in such a school. Look for an active and funded sports program that is a part of education, not the entire story.
Lastly, the most important thing in any high schools is the track record of graduates and what classes they offer their students. Go into the school and talk with the principal and anyone else that can help you. Walk through the school to look for cleanliness and see how the school feels. Some schools just have a better feel than other high schools. You can tell a lot about a school just by walking through with someone from the school during school hours. No school is perfect, but make sure the one you choose has what you want and where you feel your child will be safe and valued.