i try to sleep all dag if i want stay calm ...i am just kiding .....well u can do some exercise of yoga for about 15 min ...in this way u can relax and remember everything better .......you can also eat some honey of chocolate i think that this is help too
during exams, i always have my lucky ring on and of course a candy beside me, it helps me to relax... u want a tip? well my advice.. ^^ sit beside your smartest classmate.. then, there's nothing to worry about =) hehehehe