The Prophet (pbuh) said, if anyone of you intends to do something, he should offer two-Rak'at prayer other than the obligatory prayer, and then should recite the following dua. If the matter is good Allah will give the strength to do so. If the matter is bad Allah will protect us from that.

Allahumma in’nee asthakheeruka bi’ilmika wa asthaqdhiruka biqudhrathika wa as'aluka min fadhlika-l-'adheem fa innaka thaqdhiru walaa aqdhiru wa ta'lamu wala a'lamu, wa anta'allamu-l-ghuyub. Allahumma in kunta ta'lamu anna hadha-lamra khairun li fi dini wa ma'ashi wa 'aqibati `Amri va aajilihi fa-qdurhu li, Wa yassirhu li thumma baarikli feehi va in kuntha ta'lamu anna ha-dhza-l-amra sharrun li fi dini wa ma'ashi wa 'aqibati `Amri va aajilihi fasrifhu ‘anni vasrifni ‘anhu vaqdhurlil khayra haytha kaana thumma ardhini

اَللّهُمَّ إِنّيْ أَسْتَخِيْرُكَ بِعِلْمِكَ وَأَسْتَقْدِرُكَ بِقُدْرَتِكَ وَأَسْأَلُكَ مِنْ فَضْلِكَ الْعَظِيْمِ فَإِنَّكَ تَقْدِرُ وَلاَ أَقْدِرُ وَتَعْلَمُ وَلاَ أَعْلَمُ وَأَنْتَ عَلاَّمُ الْغُيُوْبِاَللّهُمَّ إِنْ كُنْتَ تَعْلَمُ أَنَّ هَذَا الأَمْرَ خَيْرٌ لِيْ فِيْ دِينِيْ وَمَعَاشِيْ وَعَاقِبَةِ أَمْرِيْ وَآجِلِهِ فَاقْدُرْهُ لِيْ وَيَسِّرْهُ لِيْ ثُمَّ بَارِكْ لِيْ فِيْهِ وَإِنْ كُنْتَ تَعْلَمُ أَنَّ هَذَا الأَمْرَ شَرٌّ لِيْ فِيْ دِينِيْ وَمَعَاشِيْ وَعَاقِبَةِ أَمْرِيْ وَآجِلِهِ فَاصْرِفْهُ عَنِّيْ وَاصْرِفْنِيْ عَنْهُ وَاقْدُرْ لِيَ الْخَيْرَ حَيْثُ كَانَ ثُمَّأَرْضِنِيْ

Meaning:
O Allah! I ask guidance from Your knowledge, And Power from Your Might and I ask for Your great blessings. You are capable and I am not. You know and I do not and You know the unseen. O Allah! If You know that this job is good for my religion and my subsistence and in my Hereafter--(or said: If it is better for my present and later needs)--Then You ordain it for me and make it easy for me to get, And then bless me in it, and if You know that this job is harmful to me In my religion and subsistence and in the Hereafter--(or said: If it is worse for my present and later needs)--Then keep it away from me and let me be away from it. And ordain for me whatever is good for me, And make me satisfied with it.
(Book: Bukhari 1166, 6352, 7390)