Assalamu 'alaykum wa ra'hmatullah . Brother , if you don't offer fardh salat , then it's unlikely that you will get any help from Allah . If you want , you can follow my advice -
1 . First of all , if you don't know shahada yet , please recite " LAA ILAHA ILLALLAHU MU'HAMMADUR RASULULLAH ( SAWLLALLAHU 'ALAYHI WA SALLAM )
2 . Now visit these links and listen to what these say
after you learn about these things , then act upon it ( ex . Offer salah , fast )
3 . Now repent to Allah sincierly . Shed a lot of tears .
4 . Join a masjid , talk to the imam , learn about islam , and act upon it .
5 . For a good result :
i doubt that you will get a good result by just praying . Your grades depend on the way you tackled your exam . However , you can try this 'amal and it might help you a lot .
On a sunday evening , after the maghrib prayer, before the waqt of 'ishaa , pray 20 raka'ats of nawfil prayers by praying 2 raka'ats at a time . You have to say sura fatiha x1 , sura ikhlas x50 , sura falaq x1 , sura naas x1 in each raka'at . After completing the nawfil prayer , say istighfar one hundred times , and duroode- mahi one hundred times. Then do du'a sincierly . Durrode-mahi :"ALLAHUMMA SAWLLI 'ALAA SAIYYDINA MU'HAMMADIN KHAIRUL KHALAIQI AFDHALUL BASHARI SHAFI'IL UMMATIN YAWMAL 'HASHRI WANNASHRI SAIYYDINA MU'HAMMADIM BI 'ADAADI KULLI MA'LUMILLAKA WA SAWLLI 'ALAA JAMI'IL AMBIAII WAL MURSALINA WAL MALA-IKATIL MUQARRABINA WA 'IBADILLAHIS SAWLIHINA WARHAMNA MA'AAHUM , BIRA'HMATIKA YAA AR'HAMAR RA'HIMIN "
ISTIGHFAR:"ASTGHFIRULLAHALLADHI RABBI MIN KULLI DHAMBIU WA TUBU ILAIHI, LAA 'HAWLA WA LAA QUWATA ILLA BILLAHIL 'ALIYIL 'ADHIM "
i tried this 'amal after an exam and i got a very good result . It might not work always , but it is a very good 'amal for gaining sawab. I , the sinner , pray to Allah that may he enable me and you and us to pass every kind of tests in this world and in the world hereafter , may he forgive us and show us the true path . AMEEN