It needn't be the case, just follow the directions to achieve great results every time, InsyaAllah.
1. Always, always, always begin with Bismillah.
2. Examine your niyaah (intention) and correct it if necessary.
3. Honour your lecturers no matter how strange their teaching methods seem to you. Respect and reverence for lecturers are amongst the distinguishing marks of being a Muslim student.
4. Begin making preparations well before the examinations begin. Plan out a REALISTIC timetable that will result in you having covered [or at least scanned] all the material well before your first exam. Use this final period to look at and attempt past exam papers and to compensate for any unforeseen delays.
5. Use your lecturers. If you have a problem, ASK!! You will find the vast majority of lecturers only to happy to help [and inadvertently give out many heavy hints as to what's on exam paper!]
6. Always revise with a sheet of paper at hand so that you can build up a list of topics which you want to discuss with your teachers. DON'T rely on your memory. If you do, you will only be reminded when you are in the exam hall trying to answer a question on your forgotten queries.
7. When revising make notes. It may seem as though you are just reproducing your notes, but persevere, believe it or not what you are doing is one of the most effective ways of revising.
8. Give yourself regular breaks, but make sure that they don't go on for longer than intended.
9. Make sure you are unlikely to be disturbed whilst studying. This means turning off the TV and asking others to answer the phone. Discipline pivotal to success.
10. Turn off the radio. Listening to haram music takes the barakah [blessings] out of your studies. If you absolutely must listen to something try some "nasyid”[Islamic Songs]
11. Always iron out problems as soon as possible. If you don't then you may well encounter problems when trying to understand the work that comes later.
12. If you are getting frustrated and feel as though you are getting nowhere then try to take comfort that from the saying of the Prophet: "For him who embarks on a path of seeking knowledge, Allah will ease for him the way to Paradise." [Muslim].
13. If you are having problems calming your nerves on exam day, remind yourself of the ultimate purpose of life and indeed the ultimate examination; before Allah [SWT] on the Day of Judgement. This should help you to put your present worries into context.
14. Before you begin on the exam paper, take a couple of minutes out to supplicate to your Lord, asking Him to grant you success only on the condition that it's good for your dean and patience in the event that it's not. Then begin in the name of Allah.
15. As you come out of the exam hall, remember to thank Allah if the exam went well. If however it didn't go as well as you had hoped, put your trust in Him. Know that such things are sent to test us and are an opportunity for us to shed some of our sins and show our contentment with his divine decree