Seeing how most of your are still in high-school i figured I'd help you out by sharing some of the methods I used to help me graduate
*Chapstick- if you happen to take a scantron test and you don't know any of the answers just randomly fill in the bubbles and rub chapstick all over your answer sheet this makes your scantron unreable and the machine will usually eat it your answer sheet when your teacher gives you a day to make up the test tell him/her you have a dentist appointment or something and that you'll be able to make it up the next day. this should buy you a couple days.
*Broken Pencil- An old school method. just break your #2 pencil get up and go sharpen it make sure you to look at answers on the way back you should be able to get 2 or 3. Only do this about twice per test and space out your get-ups
*Imprint- Before you take the test [preferably in another class], take out a few blank sheets of paper and line them all up on your desk in a stack. Take a ballpoint pen, and on the top sheet in a corner where you dont usually write on tests, write with a pretty good pressure what you need to know for the test [answers/info/etc.] to leave a blank imprint on the next page. Use that next page for your test. When your taking the test you can still read the imprint off the paper and by the time the teacher gets the paper, the imprint won't be noticible unless they're really looking for it. To be safe, scratch the underside of the page a little to take it away when you're done.
*Decorative Code-This is used best when written in code, and if you really need a LOT of notes with you. Write all your notes, in code, with permanent pen or paint, all over something you can take with you to class. Try to write in patterns in some kind of creative way, so if a teacher asks you what it is you can say it's just meaningless decoration or something.
*The Bathroom- If your teacher will actually LET you go, stash your books and notes in the bathroom, during the test make a list of everything you DON'T know the answer to, then ask to go to the bathroom, look it all up (if you have a bad memory, write it down somewhere), then go back to the test and fill it all in.
*Eye Contacts- act like you have somthing in your eye and touch ur eye acting like ur getting an eye lash out or fixing a contact that way u can look all over the place including some ones paper. the teacher wont suspect a thing
*Camera Phones- If possible have one of your friends distract the teacher while you take a picture of the test on your camera phone go home and look up all the answers
*Look around the room (if you're writing the test in the room you normally have the subject in). Posters on the walls, books, things like that might give you clues
*When you don't know the answer to a question (for like English or humanities tests) - BE AS VAUGE AS POSSIBLE. This way the teacher can't count it wrong and you can explain your answer later when you know what it is
*Don't look puzzled or confused, or the teacher might get suspicious.
*Be clever when you hide notes. most teachers are old as shit and have seen it all
*Watch your teacher! When the teacher is turned away or occupied, ask friends for answers
* When writing papers write the entire thing in size 12 font then go back and change the font size on all the periods to 14. it's unoticeable to teachers and on papers over 5 pages will usually save you about 1/2 to 3/4 of writing.
The Golden Rule
*sit next to Asian people