The Prophet (p.b.u.h) used to teach us the way of doing Istikhara (Istikhara means to ask Allah to guide one to the right sort of action concerning any job or a deed), in all matters as he taught us the Suras of the Quran.
He said, "If anyone of you thinks of doing any job he should offer a two Rakat prayer other than the compulsory ones and say (after the prayer): 'Allahumma inni astakhiruka bi'ilmika, Wa astaqdiruka bi-qudratika, Wa as'alaka min fadlika al-'azlm Fa-innaka taqdiru Wala aqdiru, Wa ta'lamu Wala a'lamu, Wa anta 'allamu l-ghuyub. Allahumma, in kunta ta'lam anna hadha-l-amra Khairun li fi dini wa ma'ashi wa'aqibati amri (or 'ajili amri wa'ajilihi) Faqdirhu wa yas-sirhu li thumma barik li Fihi, Wa in kunta ta'lamu anna hadha-lamra shar-run li fi dini wa ma'ashi wa'aqibati amri (or fi'ajili amri wa ajilihi) Fasrifhu anni was-rifni anhu. Waqdir li al-khaira haithu kana Thumma ardini bihi.' (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)."
The Prophet added that then the person should name (mention) his need.