Here's my revision tips:
Start revising early
— i.e. months, not days before the exam. Make a timetable (see samples) to plan your revision and stick to it.
Don't spend ages making your notes look pretty
— this is just wasting time. For diagrams, include all the details you need to learn, but don't try to produce a work of art. Limit yourself to 2 or 3 colours so you don't get carried away colouring things in.
Take short breaks
— every hour, not every 10 minutes.
Use revision guides
— CGP ones are the best you can buy(blatant CGP advert, I know, but what do you expect — you're on our website...)
Sleep on your exam notes
— this will enable you to revise by osmosis. If you are going to do this , it's best not to learn anything until the night before the exam. Stick a revision guide under your pillow and when you wake the next day, you'll find the full contents of the book have been absorbed into your brain.
In study leave, start revising early
i.e. 9am — that way you'll get your day's work done much quicker and will have time to relax in the evening.
Stick revision notes all around your house
so in the exam you think — "aha, quadratic equations, they were on the fridge..."
Get yourself drinks and snacks
so you don't make excuses to stop every 10 minutes...
Try reading difficult bits in funny accents
— Australian is particularly good... It worked for my friend Alice (the weirdo).
Sit at a proper desk
Don't try to revise in bed — you'll be in the land of pink igloos and elephants before you can say "Captain Birdseye".
Don't put it off
"Procrastination" is the long word for it. And it means rearranging stuff on your desk, getting a sudden urge after 16 years to tidy your room, playing the guitar, thinking about the weekend, writing love poems about that girl/boy you fancy, painting your toenails, etc, etc, etc,... Sit down at your desk and GET ON WITH IT.
Don't just read your notes
— you have to WRITE STUFF DOWN. This is real basic "how to revise" stuff. For the full details, get yourself a copy of our "How to Revise" book.
Take in a beer mat
To beat the wobbly exam desk — this will do your nerves and general mental state no end of good...
Don't turn yourself into a revision zombie
— if you stop doing anything else but revision you'll turn into a zombie. It's really important that you keep time to do things you enjoy... like cinema, shopping, sports, frisbee, rock-climbing, making model planes, nose-picking, whatever tickles your ferret... When you're doing these try to relax and totally forget about revision.
Do lots of practice exam papers
This is especially important as you get close to the exams — CGP has plenty available (another blatant advert).
Read the exam timetable properly
— double-check so you don't miss an exam and have plenty of time to prepare for it.
If really stuck in the exam... play the earthquake game
— throw all your pens in the air and they'll form the name of a city about to be hit by an earthquake.
Find the right environment to revise
NOT in front of the TV. NOT listening to the radio. Music can sometimes be OK, but you need to find the right kind. It's got to be something that's just there in the background that you're not thinking about at all. Music without singing is better as you won't be tempted to dance around your bedroom like a big fool.
Don't hang around with the nervous paranoid
people on the morning of the exam. — they'll just stress you out, which doesn't help at all.
Look at the new CGP tips books
— to get advice specific to your subject, e.g. Maths tips.
Dress as a medieval knight and demand ale
— this is an old tradition, which states that anyone attending the examination in full knight's costume has the right to demand a tankard of ale. Unfortunately, you need to be carrying a sword and if you try this you'll be arrested and sent to prison. 
