O Allah, make it easy and do not make it difficult, and complete it with goodnes — Success
اللَّهُمَّ يَسِّرْ وَلَا تُعَسِّرْ وَتَمِّمْ بِالْخَيْرِ
Transliteration: Allaahumma yassir wa laa tu'assir wa tammim bil-khayr
Translation: O Allah, make it easy and do not make it difficult, and complete it with goodness.
Reference: General supplication