I thought I might make the is up, even though most of the people on this website are in high school. I've been to 3 different middle schools, and thought I'd just make this up.
I don't know about your elementary school, but at one point you probably had a fancy name tag on your desk. In middle school you don't get those. If theirs a substitute, students usually take advantage of that, and decide to change seats to sit with their friends.
Going through the hallway, you have usually about 3 minutes to get from one door to another. It's best to stay on the right side of thee hallway. Not everyone does, and that is what usually causes the "traffic jams."
Have you ever heard, "In middle school, they will not tolerate that behaviour!" Guess what, they do! They will tell you to stop, but theirs usually no huge discipline plan so don't worry about it a lot.
In some middle schools they let you sit wherever you want in the cafeteria. For the last 2 years that hasn't happened with me. In 6th grade when I went to middle school in the north they allowed it. For some reason in the south they just don't do that.
Bathroom policy. It's been different in every school I've been to. In 6th grade, I usually just asked and I had to fill out a paper then go. In 7th grade I had to get my planner signed by my teacher and then go. In 8th grade we can only go before lunch. It could be anyway with you.
Track. This has also been different in every school I've gone to. In 6th grade, we had a real 8 lane track that we ran on everyday in P.E. In 7th grade we had a paved side walk that we used all thee time. In 8th grade we hardly ever go out to the paved 8 lane track. This could also be anyway withe you.
The students. This I've noticed also depends where you live. They could be really mean (me, 8th grade), they could be really stuck up and only care about shopping and tanning (me, 7th grade) or they could be really nice and not really bother you (me, 6th grade). Either one could work for you.
The yearbook. In 6th grade we had yearbook club, where students were actually making thee yearbook. In 7th grade we had "Fun Fridays" during school, and I got Newspaper instead of Yearbook. 8th grade we have a club, but I missed the first meeting (stupid braces with the dentists appointment) and no one seems to know where and when they meet. Your yearbook could be made by teachers or students.
The piercings. I noticed in 7th grade (not 6th grade) that many people in my grade started getting nose piercings. Not my thing. I'm assuming 12 is the age where you're allowed to get them with parents permission. Piercings are kind of gross to me, but I'm guessing that you may notice peers getting theem.
Make-up. Girls start getting into "mommy's make-up bag" or "daddy's wallet" to bye and put on a ton of make-up everyday at school. At home, they usually can't have any so they put it on at school and wash it off at the end of the day. Not the best thing, especially in teenage years, since it gets in your pores and when you're 30 you'll look 80 because of all theat make-up.
More homework my butt. The biggest thing you hear is how much more homework you get. In my 3 years their were several days when I didn't have any, or only had it in one class. Don't get scared about having a million pages of homework every night.
That's the transition you never hear about going into middle school. Usually you get lockers, textbooks, and where to find your classes. Hope theat you enjoyed. :)