Below are my favorite duas that I practised when I was a student.
- Dua for a quick understanding and absorption of subject from Surah Taha verse 25-28
رب اشرح لي صدري. ويسر لي أمري. واحلل عقدة من لساني. يفقهوا قولي.
Rabbishrahli sadri, wa yassir li amri, wahlul uqdatan min lisanii yafqahu qaulii.
Which Means:
O My Lord, expand for me my breast (with assurance). And ease for me my task. And untie the knot from my tongue. That they may understand my speech.
- Dua for quick understanding and good memory
اللهم إني أسألك فهم النبيين,وحفظ المرسلين, وإلهام الملائكة المقربين, في عافية يا أرحم الراحمين.
Allahumma inni as aluka fahman nabiyyiin, wa hifzhal mursaliin, wa ilhamal malaaikatil muqorrobiin, fii 'aafiyatin ya Arhamar Raahimiin.
O Allah, I ask of you the understanding of the prophets, the memory of the messengers, and the inspiration of the angels that are close to You, all in good health, O Most Merciful of all who displays mercy.
- Dua after revision
اللهم إني أستودعك ما علمتنيه فاردده إلي عند حاجتي إليه.
Allahumma inni astaudi'uka ma 'allamtaniihi, fardud hu ilayya 'inda hajatii ilaihi.
O Allah, I place with You the knowledge that You have taught me for safeguarding, that You may return it to me in my time of need.
- Dua when sitting for the examination
ربي يسر ولا تعسر, ربي تمم بخير ياكريم
Rabbi yassir wa la tu'assir, Rabbi tammim bi khair Ya Kariim
O My Lord, ease (my task) for me and do not make it difficult for me, O My Lord, end (my task) with a good ending, O Gracious One.
I would also practise reading Surah Al-Insyirah (seven times) and Surah Al-Fath (once) when dealing with a particularly difficult subject before revision.
Hope the above helps.
Wallahul Musta'an.