Generally speaking, students should implore Allah to help them make the best use of their time during the school or study days in a beneficial way, and to enable them to serve Him better. Always realize that success is from Allah Alone, which means that they should seek His Guidance. Implore Him to make them succeed in their studies and to apply what you have learned.
Seeking Allah’s Help not only reminds us of our Lord, but also puts everything into its rightful place. It reminds us that we are so completely dependent upon Allah, whilst He is free of any need.
thus, whomever Allah is with, then that person is a troop, which is never defeated, and a soldier who does not fall and a guide who does not mislead.
Focusing on the issue of du`a if one faces difficulty in the exams, Sheikh Ja`far Ahmad At-Tahlawi, the prominent Azharite scholar, states: “If you face any difficulty during the exams or even if you want to achieve remarkable success in gaining useful knowledge, you should implore Allah from the depth of your heart to grant you that useful knowledge and to make things easy for you. It is also better to implore Allah while reciting the following verses: “(Moses) said: My Lord! Relieve my mind. And ease my task for me; And loose a knot from my tongue. That they may understand my saying.” (Taha: 25-28)”

You can also resort to Allah with du`a’ with whatever wording you like. You can implore Him saying, “My Lord! Relieve my mind and ease my task for me.”