Decorating a high school classroom is harder in today's day and age than it was years ago. Teenagers are more grown up at this age making regular decorations seem boring. The trick is provide fun, entertaining and wholesome decorations without making the teens feel like they are little kids.
Decorate your own teacher's desk with personal items. Let the teens feel like they can get to know you. Make sure you don't use anything valuable or that can't be replaced. Use pictures that have duplicates in case any get lost or stolen. Make sure all of your pictures are descent and can't cause any controversy. If you love animals bring in some animal artifacts and decorate your desk with them. Whatever your passion is use that to gain the children's attention and use your desk as a way to start up some conversations.
Use the modern media to get your message across. For instance, when Pirates of the Caribbean came out so did a poster of Orlando Bloom reading a book. The poster promoted reading. This would have been a great poster to add to your classroom. Some other posters to consider are ones for movies that are based on books. Beowolf was just released in theaters and is often a book that is required to be read in high school. A poster of this movie may be a great addition to your classroom.
Hang up a white board by the hallway door. Add a new quote to the board each day. Hang a suggestion box next to the white board and allow the students to submit their own quotes. Some immature teenagers will submit nonsense, but it is worth weeding through the bad submissions to find the good ones. This exercise encourages teenagers to use their brains and either come up with their own quotes or find some great ones by doing a little research.
Have the kids help out. There are several things you may want to consider doing. First, you could have your students write up a poem about the subject matter you are studying. You could then buy some frames at the dollar store and place the poems around the room. Second, you could have the students paint a scene from whatever they are learning about. If they are learning about the solar system they could paint a space theme, or if they are learning about Colonial Times they could paint a colonial house or family. If your class is studying Literature have your students paint a picture of the story you are currently working on. Frame all of the pictures and hang them so that the teens know this is their classroom too.
Create a hero's corner. This should be a section of your classroom decorated for heroes. The people posted in this section should be people from the past and the present. These should be people who your teenagers can look up to. You may want to have some inventors, a president, some soldiers, and even some sports players who have done something special. Include some articles of local heroes. Add new stuff each week and encourage your students to read the newspapers and let you know of any new heroes.
Have a section dedicated to artwork. You may not want to hang up a real painting, but there are plenty of ways to display knock-offs of the real thing. You don't need a lot of room for this. Just enough space for one painting and switch it once per week. Add an informational sheet next to the painting describing the painting, who painted it, what era it is from, and what the artists inspiration was. The kids will learn about art without even realizing it. They are also bound to check out that area each week as their curiosity will get the better of them.
Add a comedy corner. Use jokes that you may find online or comedy strips from that days newspaper. Encourage kids to submit their own comedy pieces to be displayed in that area. Laughter really is the best medicine and it is a great idea to keep some humor in the classroom. Make sure all jokes and comedy strips are clean and contain no offensive pictures or words.
Set up the students desks in different formations each week. Have them space out in a square one week and in the shape of an M the next. Keep those kids on their toes and give them something fun to look forward to. They may think you are a little crazy, but when they see you put in extra time for them, they are going to appreciate it. Your best bet is to switch the desks every Wednesday to give the kids something to look forward to mid week.
Don't decorate your classroom once and leave it that way all year. You will quickly bore your students and that can lead to a lack of stimulation. Bored kids end up getting rowdy and causing problems in the classroom.
Get some ideas from the students as to what they might like to see in the classroom.