Well, I was giving advice to Sarah, and then I found out, that I should have a guide to how to not look like you're a loner somewhere :) Don't worry, I look like a loner at art, and these are some stuff I do to try to look 'cool' :)
don't you think kim kardashian is pretty?
If you are always early, you have to wait and you probably will get embarrassed if you see someone coming from your class. Here's what you do. Get your phone out, and pretend to be texting, looking preoccupied in something so intent. Try not to look up and around your surroundings because then, people know you're faking. Also, try not to act too 'cool' because then you just look a bit weird.
If you think texting is a bit..mm, then try calling. To get this right, ACTUALLY call someone, someone who you can call for free :) so that you can pretend to be talking and look wowing at the same time. Also, try not to be too loud or else people will think you're try-hardish. You know, I call my sister because I call her for free, and she just puts me on loud-speaker and listens while she does her own stuff. The sad thing is, she has headphones in, so she doesn't bother listening to me, so it's just me talking to no one on the other end :(
Well, if you're lucky to spot someone you actually know a bit or quite well, talk to them. Try to keep them talking for a long time so you can stall the time from before the class stars and when class actually starts. This way, people will think you're normal and well-knownish because you have friends to talk to :)
This relates back to number 3, but when you go into class (assuming you and your friend are in the same class), try to sit with them, close to them and continue talking until the teacher enters. If not, be really friendly to another loner and talk to them, so you kill two birds with one stone - if that's how it's said.
If there's not one, you could always find somewhere to sit and do something aka homework. Try not to read a book, or else people think you're a bookworm reading by yourself which totally contradicts with this guide. Try doing homework, preferably something really smart, like showing off your Year 10 Maths Textbook in your Year 9 English class. Don't show off too much though, or else people will think you're stuck up, and that's not good.
Sometimes, none of these things work, so just dress nicely :) Stand somewhere, where not many people are around, but an alright amount of people are there. Dress in something really cool and have your cool bag there (with your stuff inside). Let your eyes do the wandering and try to act innocent and unaware of your surroundings. When class starts, and you see someone staring at you, give them a huge smile while entering class because then they think, "Wow, what a confident person, so pretty as well :)"
Now, if none of these work, then I am so sorry. Try to find something that makes you look cool and try it out :)