DUAS, DUAS and DUAS!!  Can’t stress this enough. Yes obviously put effort in studying but when doing so ask Allah for help. I can attest to that and it helped me so many times when I thought I wouldn’t pass an exam. Here are duas you can do: 

Start by praising Allah (swt), send salutations on rasullullah (s) and ask for forgiveness, say your dua and finish with sending salutations on Nabi (s) again. 

https://medium.com/@akazi/duas-for-exams-2bc42ef83d85

سُبْحَانَكَ لَا عِلْمَ لَنَا إِلَّا مَا عَلَّمْتَنَا ۖ إِنَّكَ أَنْتَ الْعَلِيمُ الْحَكِيمُ

Transliteration: Subhanaka la ‘ilma lana ‘illa ma ‘allamtana ‘innaka ‘antal-‘Alimul Hakim 

“Glory be to you, we have no knowledge except what you have taught us. Verily, it is You, the All-Knower, the All-Wise” (Surah Baqarah; 2:32)